Which of the following hormones acts on the mammary glands and stimulates the formation of alveoli?

Progesterone also acts on the mammary glands and stimulates the formation of alveoli (sac-like structures which store milk) and milk secretion.

Oestrogens stimulate the formation of the ductal system of mammary glands.

Prolactin stimulates milk formation and secretion.

Oxytocin stimulates milk ejection.