What is the process called when the mammary glands start producing mi…

The correct answer is Option (3) → Lactation

During pregnancy the mammary glands of the mother undergo differentiation, and towards the end of pregnancy they start producing milk. This process is called lactation, and it helps the mother feed the new-born. Gestation is the period of pregnancy itself, parturition is the delivery of the foetus and ovulation is the release of the ovum from the ovary.

NCERT Extract:
Parturition and Lactation – “The average duration of human pregnancy is about 9 months which is called the gestation period. Vigorous contraction of the uterus at the end of pregnancy causes expulsion/delivery of the foetus. This process of delivery of the foetus (childbirth) is called parturition.”
Parturition and Lactation – “… The mammary glands of the female undergo differentiation during pregnancy and starts producing milk towards the end of pregnancy by the process called lactation. This helps the mother in feeding the new-born.”