Doctors mistook simple menstraul cramps

[joehurundas]

Doctors in the early twentieth century commonly mistook endometriosis as simple menstrual cramps and informed women that there was no medical cure for their condition.

A. ....
B. endometriosis for simple menstrual cramps
C. simple menstrual cramps for endometriosis
D. endometriosis to be simple menstrual cramping
E. endometriosis and simple menstrual cramps

From the original sentence, doctors mistook X as Y (rather than "mistook X for Y"). The other challenge, or so to say, is to identify what elements are X and Y; thought one could simple match the original question to X (endometriosis) and Y (simple menstrual cramps).

Is this correct, or am I missing something else?

[tim]

i'm afraid i don't see what the issue is here. It's pretty obvious what X and Y are here, and yes the correct idiom is mistake X FOR Y. The only real question here is whether X and Y could be reversed (as in the case of C), but the context provides the clue here - they mistook a more complicated X for a simple Y. What is the source on this one BTW? i can't find it in our CAT database?