Question:
Who was the chair of United States Senate Committee on the District of Columbia in May, 1816?

Context:
 Armistead Thomson Mason is the chair of United States Senate Committee on the District of Columbia from Jan, 1816 to Jan, 1817. 
 James Barbour is the chair of United States Senate Committee on the District of Columbia from Jan, 1821 to Jan, 1823. 
 Robert Henry Goldsborough is the chair of United States Senate Committee on the District of Columbia from Jan, 1817 to Jan, 1819.

Answer:
Question:
Who was the chair of United States Senate Committee on the District of Columbia in May, 1816?

Context:
 Armistead Thomson Mason is the chair of United States Senate Committee on the District of Columbia from Jan, 1816 to Jan, 1817. 
 James Barbour is the chair of United States Senate Committee on the District of Columbia from Jan, 1821 to Jan, 1823. 
 Robert Henry Goldsborough is the chair of United States Senate Committee on the District of Columbia from Jan, 1817 to Jan, 1819.

Answer:
user
Armistead Thomson Mason
assistant
Question:
Who was the chair of United States Senate Committee on the District of Columbia in May, 1816?

Context:
 Armistead Thomson Mason is the chair of United States Senate Committee on the District of Columbia from Jan, 1816 to Jan, 1817. 
 James Barbour is the chair of United States Senate Committee on the District of Columbia from Jan, 1821 to Jan, 1823. 
 Robert Henry Goldsborough is the chair of United States Senate Committee on the District of Columbia from Jan, 1817 to Jan, 1819.

Answer:
user
James Barbour
Robert Henry Goldsborough
assistant
Question:
Who was the chair of United States Senate Committee on the District of Columbia in May, 1816?

Context:
 Armistead Thomson Mason is the chair of United States Senate Committee on the District of Columbia from Jan, 1816 to Jan, 1817. 
 James Barbour is the chair of United States Senate Committee on the District of Columbia from Jan, 1821 to Jan, 1823. 
 Robert Henry Goldsborough is the chair of United States Senate Committee on the District of Columbia from Jan, 1817 to Jan, 1819.

Answer:
user
Armistead Thomson Mason
assistant