Sentence Correction

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Ok here is the question:

Forced to cut back their stock, automobile dealers in the area have cut prices; their pick-up trucks have been priced to sell, and they are.
A)
B) are priced to sell, and they have
C) are priced to sell, and they do
D) are being priced to sell, and have
E) had been priced to sell, and they have

I have the answer key but the explanation given in the book is too short, and I am unable to understand anything from it. So please try to elaborate your reasoning.