Open seat elections are elections in which:
A. voters don't know the party affiliation of the candidates
B. voters can vote for any candidate, regardless of party
C. an incumbent faces a serious, well-funded challenger
D. an incumbent runs unopposed
E. no incumbent is running for reelection
If you think about the meaning of the words in the term for this sort of election, you will be able to figure out the right answer.
When we talk about the “seat” in this phrase, we are talking about a position in government, usually in Congress or a state legislature. If we say that the seat is “open,” it implies that there is no one “sitting” in that seat at the moment. If there is no one sitting in the seat at the moment, that means that there is no incumbent in the race. This means that Option E is the correct answer. The only other option that is even close is Option B. However, that is referring to something called an “open primary,” not an open seat.
An open seat election is an election where there is no incumbent running.