SC: As it is with traditional pharmacies, online drugstores

[cesar.rodriguez.blanco]

I have doubts in this SC:
A) wrong because of it (no antecedent). Can be the "impersonal" it, such as "it is sunny?
B) I do not why is it wrong. Is it because of the parallelism?
C) Correct. "As is......prescriptions are...."
D) Distorts the meaning: It says that traditional pharmacies "are" online drugstores
E) Wrong because of LIKE. The cornerstone are not similar to traditional pharmacies.
Is correct "the cornerstone...IS prescriptions" or "the cornerstone.....ARE prescriptions"?
Please help me know if I am correct and solve my doubts.

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

[RonPurewal]

here's a long thread about this question
as-it-is-with-traditional-pharamacies-on-line-drugstores-t2420.html

check out that thread, and, if you still have questions, please re-post them on THAT thread (not this one).

thanks.