What Occurs During the Proliferative Phase of the Uterine Cycle

What occurs during the proliferative phase of the uterine cycle?

A) While the ovarian follicles are producing increased amounts of estrogen, the endometrium prepares for possible fertilization with pronounced growth.
B) If fertilization does not occur, the corpus luteum degenerates and hormonal levels fall.
C) Withdrawal of hormones causes the endometrial cells to change, and menstruation begins.
D) Maturation of an ovum is completed.