How Do Voter Attitudes Serve as a Barrier to Minor

How do voter attitudes serve as a barrier to minor parties in government?

A) Americans increasingly identify as Republican or Democrat.
B) Americans overwhelmingly favor a two-party system.
C) Americans often believe a minor-party vote is a wasted vote.
D) Americans fear the federal penalty for breaking Duverger's law.
E) Americans largely fail to realize the barrier is merely psychological.