(A) when unaccompanied correspondingly by increases in sales, can lead - Usage of When is wrong
(B) when not accompanied by corresponding increases in sales, possibly leads - Usage of When is wrong
(C) when they were unaccompanied by corresponding sales increases, can lead - Usage of When is wrong
(D) if not accompanied by correspondingly increased sales, possibly leads - Subject verb agreement (inventories and leads)
(E) if not accompanied by corresponding increases in sales, can lead - Correct

(A) when unaccompanied correspondingly by increases in sales, can lead ("WHEN" CHANGES THE MEANING/"CORRESPONDING INCREASES" IS BETTER THAN "CORRESPONDINGLY")
(B) when not accompanied by corresponding increases in sales, possibly leads ("CAN LEAD" IS OK)
(C) when they were unaccompanied by corresponding sales increases, can lead (WHEN CHANGES THE MEANING)
(D) if not accompanied by correspondingly increased sales, possibly leads ("CAN LEAD" IS OK/"CORRESPONDING INCREASES" IS BETTER THAN "CORRESPONDINGLY")
(E) if not accompanied by corresponding increases in sales, can lead (CORRECT)

If there is something wrong about my explanation, please let me know!

OA is E

I am assuming your question to begin with, and reason for posting this sentence, is when to use When and when to use If.

Someone correct me if this is wrong:

When can't be used if there is a possibility something might happen.

When I take a shower I may smell better. Would thus be incorrect. If the sentence read: When I take a shower I will smell better. That would mean I know I will smell better.

vs.

If I take a shower, I might smell better. Would be correct since you are saying if I do this, something might happen. Vs When I do this, I know something will happen. Therefore: When I take a shower, I might smell better. would be incorrect.

Again I am no GMAT expert so please correct me if I am wrong so I can learn!

Thanks