Use the Graph Below, Which Shows Changes During the Menstrual $\mathrm{C}$

Use the graph below, which shows changes during the menstrual cycle, to answer the following Questions

-The source of the increase in concentration indicated at point $\mathrm{C}$ is the

A) hypothalamus
B) anterior pituitary
C) corpus luteum
D) ovary
E) adrenal cortex