Which of the Following Is a Basic Principle of Proportional

Which of the following is a basic principle of proportional representation?

A) The number of years a representative serves should be proportional to the level of support he or she receives from voters.
B) Cross-pressured representatives who are not beholden to a political party tend to make the best decisions.
C) The number of seats a party wins in the legislature should be proportional to the level of support it receives from voters.
D) A political system must provide representation for multiple minor parties in order to adequately represent voters.