Most Democratic Countries Elect Legislatures Through One of Two Types

Most democratic countries elect legislatures through one of two types of electoral systems: single-member district or proportional representation. In single-member district systems, citizens in specific areas vote for candidates who represent their districts. In proportional representation systems, citizens in the country vote for political parties. Parties are then awarded seats in the legislature proportionate to the percentage of the vote they have won. In other words, if a party wins 20 percent of the vote, it receives 20 percent of the seats in the legislature. Why will countries with proportional representation systems tend to have more political parties than those with single-member district systems?

A) Only large countries tend to use proportional representation systems, and these countries naturally have more parties.
B) Countries with proportional representation systems tend to be more sharply divided along ethnic and regional lines, and many parties tend to arise as groups struggle to defend their interests.
C) Parties in proportional representation systems do not have to win a majority of the vote in any district, so it is easier for smaller parties to gain representation in the legislature.
D) Countries with proportional representation systems tend to have constitutions that mandate the existence of more than three political parties.