Question:
Who was the head of Sofia in Nov, 1998?

Context:
 Todor Zhivkov is the head of the government of Sofia from May, 1949 to Nov, 1949. 
 Stefan Sofiyanski is the head of the government of Sofia from Nov, 1995 to Jun, 2005. 
 Aleksandar Karakachanov is the head of the government of Sofia from Oct, 1990 to Oct, 1991. 
 Boyko Borisov is the head of the government of Sofia from Nov, 2005 to Jul, 2009.

Answer:
Question:
Who was the head of Sofia in Nov, 1998?

Context:
 Todor Zhivkov is the head of the government of Sofia from May, 1949 to Nov, 1949. 
 Stefan Sofiyanski is the head of the government of Sofia from Nov, 1995 to Jun, 2005. 
 Aleksandar Karakachanov is the head of the government of Sofia from Oct, 1990 to Oct, 1991. 
 Boyko Borisov is the head of the government of Sofia from Nov, 2005 to Jul, 2009.

Answer:
user
Stefan Sofiyanski
assistant
Question:
Who was the head of Sofia in Nov, 1998?

Context:
 Todor Zhivkov is the head of the government of Sofia from May, 1949 to Nov, 1949. 
 Stefan Sofiyanski is the head of the government of Sofia from Nov, 1995 to Jun, 2005. 
 Aleksandar Karakachanov is the head of the government of Sofia from Oct, 1990 to Oct, 1991. 
 Boyko Borisov is the head of the government of Sofia from Nov, 2005 to Jul, 2009.

Answer:
user
Todor Zhivkov
Boyko Borisov
Aleksandar Karakachanov
assistant
Question:
Who was the head of Sofia in Nov, 1998?

Context:
 Todor Zhivkov is the head of the government of Sofia from May, 1949 to Nov, 1949. 
 Stefan Sofiyanski is the head of the government of Sofia from Nov, 1995 to Jun, 2005. 
 Aleksandar Karakachanov is the head of the government of Sofia from Oct, 1990 to Oct, 1991. 
 Boyko Borisov is the head of the government of Sofia from Nov, 2005 to Jul, 2009.

Answer:
user
Stefan Sofiyanski
assistant