All the answer choices end in 'auxiliary' or 'helper' verbs that are not followed by a main verb. This is okay when the rest of the sentence makes clear what the main verb is. E.g. "She thinks I run fast, and I do" (run fast). I don't need to include the second
run fast because the first part of the sentence makes clear that
run is the main verb attached to the auxiliary verb
do. But for sentence like this, the helper verb still must agree with the main verb as written in the rest of the sentence. For example, I can't say "she thinks I run fast and I am" (run fast) because 'I am run fast' is incorrect.
If we add the main verb at the end of each of the answer choices we get:
(A) have been priced to move and they are (move)
(B) are priced to move, and they have (move)
(C) are priced to move, and they do (move)
(D) are being priced to move, and have (move)
(E) had been priced to move, and they have (move)
C is the only answer choice in which the helper verb agrees with the main verb.