Question:
Who was the chair of National Cancer Institute in Dec, 2016?

Context:
 Douglas R. Lowy is the chair of National Cancer Institute from Apr, 2015 to Oct, 2017. 
 Norman Sharpless is the chair of National Cancer Institute from Oct, 2017 to Dec, 2022. 
 Harold E. Varmus is the chair of National Cancer Institute from Jan, 2010 to Jan, 2015.

Answer:
Question:
Who was the chair of National Cancer Institute in Dec, 2016?

Context:
 Douglas R. Lowy is the chair of National Cancer Institute from Apr, 2015 to Oct, 2017. 
 Norman Sharpless is the chair of National Cancer Institute from Oct, 2017 to Dec, 2022. 
 Harold E. Varmus is the chair of National Cancer Institute from Jan, 2010 to Jan, 2015.

Answer:
user
Douglas R. Lowy
assistant
Question:
Who was the chair of National Cancer Institute in Dec, 2016?

Context:
 Douglas R. Lowy is the chair of National Cancer Institute from Apr, 2015 to Oct, 2017. 
 Norman Sharpless is the chair of National Cancer Institute from Oct, 2017 to Dec, 2022. 
 Harold E. Varmus is the chair of National Cancer Institute from Jan, 2010 to Jan, 2015.

Answer:
user
Harold E. Varmus
Norman Sharpless
assistant
Question:
Who was the chair of National Cancer Institute in Dec, 2016?

Context:
 Douglas R. Lowy is the chair of National Cancer Institute from Apr, 2015 to Oct, 2017. 
 Norman Sharpless is the chair of National Cancer Institute from Oct, 2017 to Dec, 2022. 
 Harold E. Varmus is the chair of National Cancer Institute from Jan, 2010 to Jan, 2015.

Answer:
user
Douglas R. Lowy
assistant