Question:
Who was the head of New York City in Dec, 1991?

Context:
 George B. McClellan, Jr. is the head of the government of New York City from Jan, 1904 to Dec, 1909. 
 John Lindsay is the head of the government of New York City from Jan, 1966 to Dec, 1973. 
 Bill de Blasio is the head of the government of New York City from Jan, 2014 to Dec, 2021. 
 Abraham Beame is the head of the government of New York City from Jan, 1974 to Dec, 1977. 
 Michael Bloomberg is the head of the government of New York City from Jan, 2002 to Dec, 2013. 
 William Jay Gaynor is the head of the government of New York City from Jan, 1910 to Sep, 1913. 
 John Francis Hylan is the head of the government of New York City from Jan, 1918 to Dec, 1925. 
 Joseph V. McKee is the head of the government of New York City from Sep, 1932 to Dec, 1932. 
 John P. O'Brien is the head of the government of New York City from Jan, 1933 to Dec, 1933. 
 Ed Koch is the head of the government of New York City from Jan, 1978 to Dec, 1989. 
 John Purroy Mitchel is the head of the government of New York City from Jan, 1914 to Dec, 1917. 
 William O'Dwyer is the head of the government of New York City from Jan, 1946 to Aug, 1950. 
 Jimmy Walker is the head of the government of New York City from Jan, 1926 to Sep, 1932. 
 Rudy Giuliani is the head of the government of New York City from Jan, 1994 to Dec, 2001. 
 Seth Low is the head of the government of New York City from Jan, 1902 to Dec, 1903. 
 Vincent R. Impellitteri is the head of the government of New York City from Aug, 1950 to Nov, 1950. 
 Fiorello H. La Guardia is the head of the government of New York City from Jan, 1934 to Dec, 1945. 
 Robert Anderson Van Wyck is the head of the government of New York City from Jan, 1898 to Dec, 1901. 
 Robert F. Wagner is the head of the government of New York City from Jan, 1954 to Dec, 1965. 
 Ardolph L. Kline is the head of the government of New York City from Sep, 1913 to Dec, 1913. 
 David Dinkins is the head of the government of New York City from Jan, 1990 to Dec, 1993.

Answer:
Question:
Who was the head of New York City in Dec, 1991?

Context:
 George B. McClellan, Jr. is the head of the government of New York City from Jan, 1904 to Dec, 1909. 
 John Lindsay is the head of the government of New York City from Jan, 1966 to Dec, 1973. 
 Bill de Blasio is the head of the government of New York City from Jan, 2014 to Dec, 2021. 
 Abraham Beame is the head of the government of New York City from Jan, 1974 to Dec, 1977. 
 Michael Bloomberg is the head of the government of New York City from Jan, 2002 to Dec, 2013. 
 William Jay Gaynor is the head of the government of New York City from Jan, 1910 to Sep, 1913. 
 John Francis Hylan is the head of the government of New York City from Jan, 1918 to Dec, 1925. 
 Joseph V. McKee is the head of the government of New York City from Sep, 1932 to Dec, 1932. 
 John P. O'Brien is the head of the government of New York City from Jan, 1933 to Dec, 1933. 
 Ed Koch is the head of the government of New York City from Jan, 1978 to Dec, 1989. 
 John Purroy Mitchel is the head of the government of New York City from Jan, 1914 to Dec, 1917. 
 William O'Dwyer is the head of the government of New York City from Jan, 1946 to Aug, 1950. 
 Jimmy Walker is the head of the government of New York City from Jan, 1926 to Sep, 1932. 
 Rudy Giuliani is the head of the government of New York City from Jan, 1994 to Dec, 2001. 
 Seth Low is the head of the government of New York City from Jan, 1902 to Dec, 1903. 
 Vincent R. Impellitteri is the head of the government of New York City from Aug, 1950 to Nov, 1950. 
 Fiorello H. La Guardia is the head of the government of New York City from Jan, 1934 to Dec, 1945. 
 Robert Anderson Van Wyck is the head of the government of New York City from Jan, 1898 to Dec, 1901. 
 Robert F. Wagner is the head of the government of New York City from Jan, 1954 to Dec, 1965. 
 Ardolph L. Kline is the head of the government of New York City from Sep, 1913 to Dec, 1913. 
 David Dinkins is the head of the government of New York City from Jan, 1990 to Dec, 1993.

Answer:
user
David Dinkins
assistant
Question:
Who was the head of New York City in Dec, 1991?

Context:
 George B. McClellan, Jr. is the head of the government of New York City from Jan, 1904 to Dec, 1909. 
 John Lindsay is the head of the government of New York City from Jan, 1966 to Dec, 1973. 
 Bill de Blasio is the head of the government of New York City from Jan, 2014 to Dec, 2021. 
 Abraham Beame is the head of the government of New York City from Jan, 1974 to Dec, 1977. 
 Michael Bloomberg is the head of the government of New York City from Jan, 2002 to Dec, 2013. 
 William Jay Gaynor is the head of the government of New York City from Jan, 1910 to Sep, 1913. 
 John Francis Hylan is the head of the government of New York City from Jan, 1918 to Dec, 1925. 
 Joseph V. McKee is the head of the government of New York City from Sep, 1932 to Dec, 1932. 
 John P. O'Brien is the head of the government of New York City from Jan, 1933 to Dec, 1933. 
 Ed Koch is the head of the government of New York City from Jan, 1978 to Dec, 1989. 
 John Purroy Mitchel is the head of the government of New York City from Jan, 1914 to Dec, 1917. 
 William O'Dwyer is the head of the government of New York City from Jan, 1946 to Aug, 1950. 
 Jimmy Walker is the head of the government of New York City from Jan, 1926 to Sep, 1932. 
 Rudy Giuliani is the head of the government of New York City from Jan, 1994 to Dec, 2001. 
 Seth Low is the head of the government of New York City from Jan, 1902 to Dec, 1903. 
 Vincent R. Impellitteri is the head of the government of New York City from Aug, 1950 to Nov, 1950. 
 Fiorello H. La Guardia is the head of the government of New York City from Jan, 1934 to Dec, 1945. 
 Robert Anderson Van Wyck is the head of the government of New York City from Jan, 1898 to Dec, 1901. 
 Robert F. Wagner is the head of the government of New York City from Jan, 1954 to Dec, 1965. 
 Ardolph L. Kline is the head of the government of New York City from Sep, 1913 to Dec, 1913. 
 David Dinkins is the head of the government of New York City from Jan, 1990 to Dec, 1993.

Answer:
user
Robert F. Wagner
John Francis Hylan
William Jay Gaynor
Robert Anderson Van Wyck
John Lindsay
Jimmy Walker
John Purroy Mitchel
Bill de Blasio
Vincent R. Impellitteri
Abraham Beame
George B. McClellan, Jr.
Fiorello H. La Guardia
Michael Bloomberg
William O'Dwyer
Seth Low
John P. O'Brien
Rudy Giuliani
Joseph V. McKee
Ardolph L. Kline
Ed Koch
assistant
Question:
Who was the head of New York City in Dec, 1991?

Context:
 George B. McClellan, Jr. is the head of the government of New York City from Jan, 1904 to Dec, 1909. 
 John Lindsay is the head of the government of New York City from Jan, 1966 to Dec, 1973. 
 Bill de Blasio is the head of the government of New York City from Jan, 2014 to Dec, 2021. 
 Abraham Beame is the head of the government of New York City from Jan, 1974 to Dec, 1977. 
 Michael Bloomberg is the head of the government of New York City from Jan, 2002 to Dec, 2013. 
 William Jay Gaynor is the head of the government of New York City from Jan, 1910 to Sep, 1913. 
 John Francis Hylan is the head of the government of New York City from Jan, 1918 to Dec, 1925. 
 Joseph V. McKee is the head of the government of New York City from Sep, 1932 to Dec, 1932. 
 John P. O'Brien is the head of the government of New York City from Jan, 1933 to Dec, 1933. 
 Ed Koch is the head of the government of New York City from Jan, 1978 to Dec, 1989. 
 John Purroy Mitchel is the head of the government of New York City from Jan, 1914 to Dec, 1917. 
 William O'Dwyer is the head of the government of New York City from Jan, 1946 to Aug, 1950. 
 Jimmy Walker is the head of the government of New York City from Jan, 1926 to Sep, 1932. 
 Rudy Giuliani is the head of the government of New York City from Jan, 1994 to Dec, 2001. 
 Seth Low is the head of the government of New York City from Jan, 1902 to Dec, 1903. 
 Vincent R. Impellitteri is the head of the government of New York City from Aug, 1950 to Nov, 1950. 
 Fiorello H. La Guardia is the head of the government of New York City from Jan, 1934 to Dec, 1945. 
 Robert Anderson Van Wyck is the head of the government of New York City from Jan, 1898 to Dec, 1901. 
 Robert F. Wagner is the head of the government of New York City from Jan, 1954 to Dec, 1965. 
 Ardolph L. Kline is the head of the government of New York City from Sep, 1913 to Dec, 1913. 
 David Dinkins is the head of the government of New York City from Jan, 1990 to Dec, 1993.

Answer:
user
David Dinkins
assistant