In twelfth-century Baghdad, Shuhda became a great religious scholar, and men as well as women had attended her lectures.
To solve this question we should know the difference between "as well as" and And.
Both has different meaning .
As well as cannot be used to mean and. The expression X as well as Y means not only Y but also X (note that X and Y are reversed).
Ajay, as well as Rahul, came to the party. [not only Rahul but also Ajay; emphasis on Ajay]
(A) men as well as women had attended her lectures - Use of "had attended" is past perfect tense which is wrong, past perfect tense is used to show sequence of events and both of the event is connected with and, so there is no sequence of event, discarded.
(B) there were men who attended her lectures as well as women -> As well as is incorrectly used here, it should men as well as woman.
(C) men as well as women attended her lectures -> Correct
(D) her lectures were given to men as well as women -> as well as should come first.
(E) her lectures were given to both men and women -> Use of and is not correct. As well as cannot be used to mean and. The expression X as well as Y means not only Y but also X (note that X and Y are reversed).