Question:
Who was the chair of United States Department of Justice in Apr, 2017?

Context:
 Jeff Sessions is the chair of United States Department of Justice from Feb, 2017 to Nov, 2018. 
 Eric Holder is the chair of United States Department of Justice from Jan, 2009 to Apr, 2015. 
 Loretta Lynch is the chair of United States Department of Justice from Apr, 2015 to Jan, 2017. 
 William Barr is the chair of United States Department of Justice from Feb, 2019 to Dec, 2022.

Answer:
Question:
Who was the chair of United States Department of Justice in Apr, 2017?

Context:
 Jeff Sessions is the chair of United States Department of Justice from Feb, 2017 to Nov, 2018. 
 Eric Holder is the chair of United States Department of Justice from Jan, 2009 to Apr, 2015. 
 Loretta Lynch is the chair of United States Department of Justice from Apr, 2015 to Jan, 2017. 
 William Barr is the chair of United States Department of Justice from Feb, 2019 to Dec, 2022.

Answer:
user
Jeff Sessions
assistant
Question:
Who was the chair of United States Department of Justice in Apr, 2017?

Context:
 Jeff Sessions is the chair of United States Department of Justice from Feb, 2017 to Nov, 2018. 
 Eric Holder is the chair of United States Department of Justice from Jan, 2009 to Apr, 2015. 
 Loretta Lynch is the chair of United States Department of Justice from Apr, 2015 to Jan, 2017. 
 William Barr is the chair of United States Department of Justice from Feb, 2019 to Dec, 2022.

Answer:
user
William Barr
Loretta Lynch
Eric Holder
assistant
Question:
Who was the chair of United States Department of Justice in Apr, 2017?

Context:
 Jeff Sessions is the chair of United States Department of Justice from Feb, 2017 to Nov, 2018. 
 Eric Holder is the chair of United States Department of Justice from Jan, 2009 to Apr, 2015. 
 Loretta Lynch is the chair of United States Department of Justice from Apr, 2015 to Jan, 2017. 
 William Barr is the chair of United States Department of Justice from Feb, 2019 to Dec, 2022.

Answer:
user
Jeff Sessions
assistant