During a home visit on the fourth postpartum day, a primiparous client tells the nurse that she is aware of a “let-down sensation” in her breasts and asks what causes it. The nurse explains that the...

During a home visit on the fourth postpartum day, a primiparous client tells the nurse that she is aware of a “let-down sensation” in her breasts and asks what causes it. The nurse explains that the let-down sensation is stimulated by which of the following?

1. Adrenalin.

2. Estrogen.

3. Prolactin.

4. Oxytocin.