Why doctors recommend breast feeding during initial period of infant growth ?

Given below are two statements: One is labelled as Assertion $A$ and the other is labelled as Reason $R$ :

Assertion $A$ : Breast-feeding during initial period of infant growth is recommended by doctors for bringing a healthy baby.

Reason $R$ : Colostrum contains several antibodies absolutely essential to develop resistance for the new born baby.

In the light of the above statements, choose the most appropriate answer from the options given below:

Which of these is not an important component of initiation of parturition in humans?

What is meant by parturition ? Describe changes occurring in uterus during this period.

In human adult females oxytocin