Third Parties Generally Cannot Win Elections Under a Majority Vote

Third parties generally cannot win elections under a majority vote system because _____.

A) the original two parties make it illegal for third parties to exist
B) the original two parties are able to use the power of incumbency to raise the large amount of money necessary to run a winnable election
C) the original two parties will have already split the voting population by placing their platforms on either side of the median voter
D) the original two parties have already "locked-in" most eligible voters as members of their parties