Please answer the following question: Information: - Friedrich Merz ( born 11 November 1955 ) is a German lawyer and politician , a former Member of the European Parliament ( 1989 -- 1994 ) , a former member of the Bundestag ( 1994 -- 2009 ) , and a former chairman of CDU / CSU parliamentary group ( 2000 -- 2002 ) . He was elected chairman of the CDU / CSU group in the same year as Angela Merkel was elected chairman of the CDU , one of the two parties constituting the CDU / CSU group . In 2002 , he stepped down as chairman in favour of Merkel . He is also a partner at Mayer Brown 's Dusseldorf office , having joined the firm 's corporate finance team in 2004 , after spending several years at Cornelius Bartenbach Haesemann . - CDU/CSU, unofficially the Union parties or Union, is the political alliance of two political parties in Germany, the Christian Democratic Union of Germany (CDU) and Christian Social Union in Bavaria (CSU). - A Member of the European Parliament (MEP) is a person who has been elected to serve as a popular representative in the European Parliament. - Germany, officially the Federal Republic of Germany, is a federal parliamentary republic in central-western Europe. It includes 16 constituent states, covers an area of , and has a largely temperate seasonal climate. With about 82 million inhabitants, Germany is the most populous member state of the European Union. After the United States, it is the second most popular immigration destination in the world. Germany's capital and largest metropolis is Berlin. Other major cities include Hamburg, Munich, Cologne, Frankfurt, Stuttgart and Dusseldorf. - The European Parliament (EP) is the directly elected parliamentary institution of the European Union (EU). Together with the Council of the European Union (the Council) and the European Commission, it exercises the legislative function of the EU. The Parliament is composed of 751 (previously 766) members, who represent the second largest democratic electorate in the world (after the Parliament of India) and the largest trans-national democratic electorate in the world (375million eligible voters in 2009). - The Bundestag ("Federal Diet") is a constitutional and legislative body at the federal level in Germany. For its similar function, it is often described as a lower house of parliament along the lines of the US House of Representatives and the Canadian or the British House of Commons. The German constitution, however, does not define the Bundestag and the Bundesrat as the lower and upper houses of a bicameral legislature. - A political alliance, also referred to as a political coalition, political bloc, is an agreement for cooperation between different political parties on common political agenda, often for purposes of contesting an election to mutually benefit by collectively clearing election thresholds, or otherwise benefiting from characteristics of the voting system or for government formation after elections. - The Christian Democratic Union of Germany (CDU) is a Christian democratic and liberal-conservative political party in Germany. It is the major catch-all party of the centre-right in German politics. The CDU forms the CDU/CSU grouping, also known as the Union, in the Bundestag with its Bavarian counterpart the Christian Social Union in Bavaria (CSU). - The Christian Social Union in Bavaria is a Christian democratic and conservative political party in Germany. The CSU operates only in Bavaria, while its larger counterpart, the Christian Democratic Union (CDU), operates in the other fifteen states of Germany. The CSU has 56 seats in the Bundestag making it the smallest of the five parties represented. After reading the paragraphs above, we are interested in knowing the entity with which 'friedrich merz' exhibits the relationship of 'member of political party'. Find the answer from the choices below. Choices: - alliance - christian democratic union - republic - union
A:
christian democratic union