Which of the following is true about the effect of hormones on libido?

A) Testosterone plays a powerful role in the libido of men but not women.
B) Progesterone is the most influential hormone for both men and women.
C) Women produce testosterone in their ovaries, which increases their libido.
D) Research has recently found that testosterone is not the primary hormone involved in human libido.

Women do produce some testosterone in their ovaries, which can play a role in their libido. However, it is important to note that other hormones such as estrogen also influence libido in women. Choices A and B are incorrect as they make broad, unsupported statements about the influence of specific hormones on libido. Choice D is also incorrect as research consistently shows that testosterone plays a significant role in human libido.