D. Women were not allowed to work in the theater, so all the performers were men.
Explanation:
This is something that is a heritage on Ancient Greek theater. Up until 1660 it was totally forbidden for women to participate in plays. Quite often, the roles of women were played by young men, so they could at least make it look like a women is presented as a character. This is interestingly also a theme of a famous movie <em>"Shakespeare in love."</em>
