Voters May Not Think Much of Parties, but Large Majorities

Voters may not think much of parties, but large majorities still admit to party preferences and use parties to guide their voting decisions for which of the following reasons?

A) because they have no real choice but to do so
B) because there is a residual irrational loyalty to parties that has outlived the usefulness of the party label
C) because party labels still provide the cheap, shorthand cue so useful to rationally ignorant voters
D) because third-party candidates have unclear messages and ill-defined goals