Secondary sexual characters in females develop in response to the hormone estrogen.

Estrogen is a crucial hormone for the female sex. The ovaries create most of the estrogen, with some estrogen made by the adrenal glands and fat cells. They are crucial to the menstrual cycle, and causes females to develop secondary sexual characteristics. Along with progesterone its also called female sex hormones. 

Progesterone, on the other hand, prepares the female body for pregnancy.

Relaxin hormone facilitates childbirth and gonadotropin hormone regulates function of ovary.

Hence the correct answer is option C.