Question:
Who was the chair of Federal Academy for Security Policy in Apr, 2008?

Context:
 Hans-Dieter Heumann is the chair of Federal Academy for Security Policy from Aug, 2011 to Sep, 2015. 
 Dieter Wellershoff is the chair of Federal Academy for Security Policy from Jan, 1992 to Jan, 1995. 
 Kersten Lahl is the chair of Federal Academy for Security Policy from Jan, 2008 to Aug, 2011. 
 Ekkehard Brose is the chair of Federal Academy for Security Policy from Oct, 2019 to Dec, 2022. 
 Günter Joetze is the chair of Federal Academy for Security Policy from Jan, 1995 to Jan, 1999.

Answer:
Question:
Who was the chair of Federal Academy for Security Policy in Apr, 2008?

Context:
 Hans-Dieter Heumann is the chair of Federal Academy for Security Policy from Aug, 2011 to Sep, 2015. 
 Dieter Wellershoff is the chair of Federal Academy for Security Policy from Jan, 1992 to Jan, 1995. 
 Kersten Lahl is the chair of Federal Academy for Security Policy from Jan, 2008 to Aug, 2011. 
 Ekkehard Brose is the chair of Federal Academy for Security Policy from Oct, 2019 to Dec, 2022. 
 Günter Joetze is the chair of Federal Academy for Security Policy from Jan, 1995 to Jan, 1999.

Answer:
user
Kersten Lahl
assistant
Question:
Who was the chair of Federal Academy for Security Policy in Apr, 2008?

Context:
 Hans-Dieter Heumann is the chair of Federal Academy for Security Policy from Aug, 2011 to Sep, 2015. 
 Dieter Wellershoff is the chair of Federal Academy for Security Policy from Jan, 1992 to Jan, 1995. 
 Kersten Lahl is the chair of Federal Academy for Security Policy from Jan, 2008 to Aug, 2011. 
 Ekkehard Brose is the chair of Federal Academy for Security Policy from Oct, 2019 to Dec, 2022. 
 Günter Joetze is the chair of Federal Academy for Security Policy from Jan, 1995 to Jan, 1999.

Answer:
user
Dieter Wellershoff
Hans-Dieter Heumann
Ekkehard Brose
Günter Joetze
assistant
Question:
Who was the chair of Federal Academy for Security Policy in Apr, 2008?

Context:
 Hans-Dieter Heumann is the chair of Federal Academy for Security Policy from Aug, 2011 to Sep, 2015. 
 Dieter Wellershoff is the chair of Federal Academy for Security Policy from Jan, 1992 to Jan, 1995. 
 Kersten Lahl is the chair of Federal Academy for Security Policy from Jan, 2008 to Aug, 2011. 
 Ekkehard Brose is the chair of Federal Academy for Security Policy from Oct, 2019 to Dec, 2022. 
 Günter Joetze is the chair of Federal Academy for Security Policy from Jan, 1995 to Jan, 1999.

Answer:
user
Kersten Lahl
assistant