Research suggests that breastfeeding benefits infants by serving as a protective factor against

Breast milk is the best food for the infants as it contains all the nutrients that infant requires. About 100 ingredients have identified in the breasts milk. Breast milk cannot be duplicated. Most of the studies suggest that breastfeeding protects infants from infections such as gastrointestinal infection, respiratory tract infections and other infectious causing diarrhea. Breast milk overall boost immune system of the baby.    

Breastfeeding is highly recommended for infants because it gives vital benefits by serving as a protective factor against wide variety of bacteria and viruses.

Moreover, researchers found out that it strengthens the infants immune system that can help protect against sudden infant death syndrome (SIDS), gastrointestinal infections, ear infections, lower respiratory infections, some autoimmune disorders such as type 1 diabetes mellitus and celiac disease, and asthma.  

the first option is ur answer : )