<s>[INST] context: The secretory phase of the menstrual cycle depends on progesterone secretion and follows the proliferative (follicular) phase. The menstrual phase occurs after the secretory phase. During the follicular phase (approximately days 4 to 16), estrogen produced by the ovaries drives cell proliferation in the base of endometrial glands and the uterine stroma. The proliferative phase culminates with ovulation. The secretory phase (approximately days 16 to 25) is characterized by high progesterone levels from the corpus luteum, a tortuous appearance of the uterine glands, and apocrine secretion by the gland cells. During this phase, maximum endometrial thickness occurs. The menstrual phase (approximately days 26 to 30) is characterized by decreased glandular secretion and eventual glandular degeneration because of decreased production of both progesterone and estrogen by the theca lutein cells. Contraction of coiled arteries and arterioles leads to ischemia and necrosis of the stratum functionale. [/INST] question: Which of the following are characteristic of the secretory phase of the menstrual cycle? | options: A: It precedes ovulation B: It depends on progesterone secretion by the corpus luteum C: It coincides with the development of ovarian follicles D: It coincides with rapid drop in estrogen levels | answer: B </s>