Why Are Breast-Fed Babies Less Likely to Contract Infectious Diseases

Why are breast-fed babies less likely to contract infectious diseases than bottle-fed babies?

A) They are less likely to come in contact with viruses and bacteria.
B) Breasts are more sterile than bottles.
C) Breast milk contains antibodies to all the diseases for which the mom has antibodies.
D) Most breast-fed babies don't leave the home often.