Question:
Who was the head of Poland in Jan, 2007?

Context:
 Tadeusz Mazowiecki is the head of the government of Poland from Aug, 1989 to Jan, 1991. 
 Jerzy Buzek is the head of the government of Poland from Oct, 1997 to Oct, 2001. 
 Beata Szydło is the head of the government of Poland from Nov, 2015 to Dec, 2017. 
 Jan Krzysztof Bielecki is the head of the government of Poland from Jan, 1991 to Dec, 1991. 
 Mateusz Morawiecki is the head of the government of Poland from Dec, 2017 to Dec, 2022. 
 Józef Oleksy is the head of the government of Poland from Mar, 1995 to Feb, 1996. 
 Jan Olszewski is the head of the government of Poland from Dec, 1991 to Jun, 1992. 
 Jarosław Kaczyński is the head of the government of Poland from Jul, 2006 to Nov, 2007. 
 Hanna Suchocka is the head of the government of Poland from Jul, 1992 to Oct, 1993. 
 Ewa Kopacz is the head of the government of Poland from Sep, 2014 to Nov, 2015. 
 Marek Belka is the head of the government of Poland from May, 2004 to Oct, 2005. 
 Kazimierz Marcinkiewicz is the head of the government of Poland from Oct, 2005 to Jul, 2006. 
 Leszek Miller is the head of the government of Poland from Oct, 2001 to May, 2004. 
 Donald Tusk is the head of the government of Poland from Nov, 2007 to Sep, 2014. 
 Włodzimierz Cimoszewicz is the head of the government of Poland from Feb, 1996 to Oct, 1997. 
 Waldemar Pawlak is the head of the government of Poland from Oct, 1993 to Mar, 1995.

Answer:
Jarosław Kaczyński