In Presidential Elections, the Unit Rule Primarily Refers to

In presidential elections, the unit rule primarily refers to

A) the law saying that if you vote for a party's presidential candidate, you must also vote for its vice-presidential candidate.
B) the practice that money spent to help a party's presidential candidate must also help its vice-presidential candidate.
C) the practice in most states of giving all the state's electoral votes to the candidate who wins a plurality of the state's popular votes.
D) the principle that every citizen should have only one vote.
E) the law stating that every member of the Electoral College has only one vote.