A Europeans have long known that eating quail sometimes makes
B Europeans have long known quail eating is sometimes able to make -- awkard wordy
C Eating quail has long been known to Europeans to sometimes make -- awkard wordy
D It has long been known to Europeans that quail eating will sometimes make - passive
E It has long been known to Europeans that quail, when it is eaten, has sometimes made –passive

A seems best ..whats the OA

Agree with sujaysolanki! Option 4 and 5 are not only having passive actions but also they are un-idiomatic. So A is the best option to chose.

OA is A

Choice D and E are both there to test your knowledge of what the GMAT DOES NOT value in an answer. Both are passive and bury the action of the sentence in a bunch of unnecessary prepositional phrases. You should be able to spot that and discard those choices on that basis. Whenever presented with a concise answer in active voice, that is the better choice, hence A is it.

Also "quail eating" is a bad construction (and kind of funny), necessary because of the awkward use of passive voice. Is there any such thing as "quail eating", per se? No. The test is not going to introduce any new linguistic constructions either, so it's probably wrong.

Thank you Danielle for the detailed explanation. Appreciate it.

No worries blanca -- glad to be of help!