Question:
Who was the head of Romania in Apr, 2007?

Context:
 Armand Călinescu is the head of the government of Romania from Mar, 1939 to Sep, 1939. 
 Gheorghe Tătărescu is the head of the government of Romania from Jan, 1934 to Dec, 1937. 
 Dimitrie Sturdza is the head of the government of Romania from Apr, 1897 to Apr, 1899. 
 Nicolae Crețulescu is the head of the government of Romania from Jun, 1865 to Feb, 1866. 
 Ion C. Brătianu is the head of the government of Romania from Jun, 1881 to Mar, 1888. 
 Nicolae Rădescu is the head of the government of Romania from Dec, 1944 to Feb, 1945. 
 Dimitrie Brătianu is the head of the government of Romania from Apr, 1881 to Jun, 1881. 
 Nicolae Golescu is the head of the government of Romania from May, 1868 to Nov, 1868. 
 Ludovic Orban is the head of the government of Romania from Nov, 2019 to Dec, 2020. 
 Adrian Năstase is the head of the government of Romania from Dec, 2000 to Dec, 2004. 
 Constantin Bosianu is the head of the government of Romania from Jan, 1865 to Jun, 1865. 
 Lascăr Catargi is the head of the government of Romania from Dec, 1891 to Oct, 1895. 
 Petre Roman is the head of the government of Romania from Dec, 1989 to Oct, 1991. 
 Petru Groza is the head of the government of Romania from Mar, 1945 to Jun, 1952. 
 Barbu Catargiu is the head of the government of Romania from Feb, 1862 to Jun, 1862. 
 Constantin Argetoianu is the head of the government of Romania from Sep, 1939 to Nov, 1939. 
 Emil Boc is the head of the government of Romania from Dec, 2008 to Feb, 2012. 
 Ion Gheorghe Maurer is the head of the government of Romania from Mar, 1961 to Feb, 1974. 
 Ștefan Golescu is the head of the government of Romania from Nov, 1867 to May, 1868. 
 Constantin Dăscălescu is the head of the government of Romania from May, 1982 to Dec, 1989. 
 Ilie Verdeț is the head of the government of Romania from Mar, 1979 to May, 1982. 
 Ion Ghica is the head of the government of Romania from Dec, 1870 to Mar, 1871. 
 Ion G. Duca is the head of the government of Romania from Nov, 1933 to Dec, 1933. 
 Ion Gigurtu is the head of the government of Romania from Jul, 1940 to Sep, 1940. 
 Take Ionescu is the head of the government of Romania from Dec, 1921 to Jan, 1922. 
 Mihai Tudose is the head of the government of Romania from Jun, 2017 to Jan, 2018. 
 Ion Emanuel Florescu is the head of the government of Romania from Mar, 1891 to Dec, 1891. 
 Constantin Sănătescu is the head of the government of Romania from Aug, 1944 to Dec, 1944. 
 Octavian Goga is the head of the government of Romania from Dec, 1937 to Feb, 1938. 
 Miron Cristea is the head of the government of Romania from Feb, 1938 to Mar, 1939. 
 Mihail Kogălniceanu is the head of the government of Romania from Oct, 1863 to Jan, 1865. 
 Theodor Stolojan is the head of the government of Romania from Oct, 1991 to Nov, 1992. 
 Radu Vasile is the head of the government of Romania from Apr, 1998 to Dec, 1999. 
 Florin Cîțu is the head of the government of Romania from Dec, 2020 to Nov, 2021. 
 Nicolae Văcăroiu is the head of the government of Romania from Nov, 1992 to Dec, 1996. 
 Theodor Rosetti is the head of the government of Romania from Mar, 1888 to Mar, 1889. 
 Victor Ciorbea is the head of the government of Romania from Dec, 1996 to Apr, 1998. 
 Sorin Grindeanu is the head of the government of Romania from Jan, 2017 to Jun, 2017. 
 Manolache Costache Epureanu is the head of the government of Romania from May, 1876 to Aug, 1876. 
 Chivu Stoica is the head of the government of Romania from Oct, 1955 to Mar, 1961. 
 Viorica Dăncilă is the head of the government of Romania from Jan, 2018 to Nov, 2019. 
 Mugur Isărescu is the head of the government of Romania from Dec, 1999 to Dec, 2000. 
 Alexandru G. Golescu is the head of the government of Romania from Feb, 1870 to Apr, 1870. 
 Dacian Cioloș is the head of the government of Romania from Nov, 2015 to Jan, 2017. 
 Victor Ponta is the head of the government of Romania from May, 2012 to Nov, 2015. 
 Gheorghe Gheorghiu-Dej is the head of the government of Romania from Jun, 1952 to Oct, 1955. 
 Petre S. Aurelian is the head of the government of Romania from Dec, 1896 to Apr, 1897. 
 Dimitrie Ghica is the head of the government of Romania from Nov, 1868 to Jan, 1870. 
 Călin Popescu-Tăriceanu is the head of the government of Romania from Dec, 2004 to Dec, 2008. 
 Gheorghe Argeșanu is the head of the government of Romania from Sep, 1939 to Sep, 1939. 
 Manea Mănescu is the head of the government of Romania from Feb, 1974 to Mar, 1979. 
 Mihai Răzvan Ungureanu is the head of the government of Romania from Feb, 2012 to May, 2012. 
 Nicolae Ciucă is the head of the government of Romania from Nov, 2021 to Dec, 2022. 
 Nicolae Iorga is the head of the government of Romania from Apr, 1931 to Jun, 1932.

Answer:
Călin Popescu-Tăriceanu