GMAT Sentence Correction (SC) | Re: Like in 2004, car sales to first-time buyers as often, if

This question is clearly not from an official source since it contains errors, however of all the errors, D is still the best choice.

main structure is X Verb Y as often as Z

I eat pears as often as apples.

First-time buyers buy cars as often as return customers. (This implies that buyers BUY return customers... should be as return customers do)