This one asks us the endometrium undergoes monthly changes under the influence of which hormones? So, the shedding of the endometrial lining or the uterine cycle is going to be primarily affected by the primary sex hormones for females, which are estrogen and progesterone, so our answer here is going to be b.
Looking at the other answer choices, we know that oxytocin is not considered a sex hormone, so it's not going to have any major influence on the uterine cycle. And while female bodies do produce testosterone, like we've talked about, and testosterone can affect female reproductive physiology in several different ways. For example, it plays an important role in sexual arousal and follicle development, testosterone does not directly affect the uterine cycle in any way. That's just going to be our primary sex hormones for females, which are estrogen and progesterone. And there you go.