Ans is C.


As it is with traditional pharmacies, on-line drugstores rely on prescriptions to be successful, since it is primarily prescriptions that attract the customers, who then also buy other health-related items.

(A) As it is with traditional pharmacies, on-line drugstores rely on prescriptions to be successful
(B) As with the case of traditional pharmacies, on-line drugstores rely on prescriptions to have success
(C) As is the case with traditional pharmacies, prescriptions are the cornerstone of a successful on line drugstore
(D) As traditional pharmacies, so on-line drugstores rely on prescriptions to be successful
(E) Like traditional pharmacies, the cornerstone of a successful on-line drugstore is prescriptions


Read the original sentence (Option A)
"

As it is with traditional pharmacies, on-line drugstores rely on prescriptions to be successful, since it is primarily prescriptions that attract the customers, who then also buy other health-related items."

what does the "It" (at the beginning) refer to?
Now check out the option C.

I picked C by using POE.


(A) As it is with traditional pharmacies, on-line drugstores rely on prescriptions to be successful
Incorrect comparison. noun phrase [on-line drugstores] is compared to a clause (it is with traditional pharmacies)!
(B) As with the case of traditional pharmacies, on-line drugstores rely on prescriptions to have success
Incorrect comparison. noun phrase [on-line drugstores] is compared to a clause (it is with traditional pharmacies)!
(C) As is the case with traditional pharmacies, prescriptions are the cornerstone of a successful on line drugstore
(D) As traditional pharmacies, so on-line drugstores rely on prescriptions to be successful
Incorrect comparison.
(E) Like traditional pharmacies, the cornerstone of a successful on-line drugstore is prescriptions
Incorrect comparison.

thanks a lot guys, I got it

It'd be nice to have an expert/tutor comment on this question. Thanks