dear Mr Pedantic, thank you very much for your contribution. but unfortunately we don't have any context as it was a question appearing in a nationwide exam. you seem to have found one. the answer is definitely E. but I just wonder whether B is acceptable in the eye of a native however hard it may be to find a suitable context.
If you ---- a car, you ---- its performance, not its appearance.
A) were buying / had been considering
B) were buying / would have considered
C) bought / had considered
D) have bought / would have been considered
E) are buying / should be considering
what I would like to know is that whether one can claim B is acceptable and equally correct.
I have found some similar mixed type sentences from the net. but they seem to be more contexualized.
EXAMPLES:
If I weren't going on my business trip next week, I would have accepted that new assignment at work.
(But I am going to go on a business trip next week, and that is why I didn't accept that new assignment at work.)
If my parents weren't coming this weekend, I would have planned a nice trip just for the two of us to Napa Valley.
(But my parents are going to come this weekend, and that is why I didn't plan a trip for the two of us to Napa Valley.)
If Donna weren't making us a big dinner tonight, I would have suggested that we go to that nice Italian restaurant.
(But she is going to make us a big dinner tonight, and that is why I didn't suggest that we go to that nice Italian restaurant.)