Prefer to, prefer than or prefer over?

Which is correct?

Our data shows that a vast majority of customers prefer Brand A  ____ Brand B.
a. to
b. than
c. over

Answer:  Both A and C are correct.

If choice B turned “than” into a conjunctive phrase by adding the comparative words “rather” or “better,” it would also be correct. (Conjunctive phrases connect two grammatical equivalents.)

Correct:

Our survey found that a vast majority of customers preferred  Brand A  to Brand B.

Our survey found that a vast majority of customers preferred  Brand A  over Brand B.

Our survey found that a vast majority of customers preferred  Brand A  rather than Brand B.

Our survey found that a vast majority of customers preferred  Brand A  better than Brand B.

Incorrect:

Our survey found that a vast majority of customers preferred  Brand A  than Brand B.