The correct answer is estrogen.
Endometrial glands are uterine glands located inside the endometrium. Their appearance varies during the menstrual cycle and it is under the influence of hormones. For example, during the proliferative phase, uterine glands appear due to estrogen secretion by the ovaries while during the secretory phase, due to increase in progesterone secretion, the uterine glands become very coiled with wide lumens and produce a secretion.
