The correct option is C During pregnancy, high levels of progesterone prevent lactation.
Progesterone is secreted by the corpus luteum. When the mature ovum is released from the mature follicle or graafian follicle, the remainder of the follicle turns into the corpus luteum.
When fertilisation takes place, the growing zygote requires progesterone for maintenance of the pregnancy, and to stop the continuation of the normal menstrual cycle.
Progesterone also promotes milk secretion and development of alveoli in the breast which are sac like structures that store milk. Also, high levels of progesterone during pregnancy prevent lactation. After the baby is delivered, the placenta is removed and the levels of progesterone decrease. This, then, allows lactation.