Please refer to the definition of words in layman's terms to know their differences:
Lactation means production of breast milk.
Sterilization is the process of getting rid of bacteria with the aid of heat.
Ovulation is the science of releasing ovules from the ovary.
Menstruation is the natural process of discharging blood and other substances from the uterus as a way of cleansing.
Based on the definitions, the correct answer is:
a. lactation
