D. All of the above.
Breastfeeding is better than formula because it leads to a lower incidence of ear inflammation, respiratory illness, and allergies.
Nutrients from breast milk strengthens the immune system of the baby. It is said that when the baby suckles, his or her saliva enters the body of the mother through her nipples and the baby's saliva will be used to detect the deficiencies that the baby has. Then, the mammary glands will produce milk filled with nutrients that will fill the baby's deficiency and boosts his or her immune system.
