Final answer:
Menarche (option b), the first menstruation of a female, generally occurs between the ages of 8 and 16, with the average age being around 12 to 13 years, marking the start of the ability to reproduce and the monthly menstrual cycle.
Step-by-step explanation:
The first menstruation of a female is known as menarche. Menarche represents a significant milestone in puberty and the development of the female reproductive system. It marks the beginning of a female's capability to reproduce and the start of the menstrual cycle. The average age for menarche is around 12 to 13 years, but it can normally occur between 8 and 16 years. The onset of menarche is influenced by a variety of genetic and environmental factors, including diet.
During menarche, the endometrium, the inner lining of the uterus, sheds and the menstrual blood flows out through the vagina, a phase known as the menses phase of the menstrual cycle. Following menarche, the menstrual cycle ordinarily becomes a regular monthly occurrence until a woman reaches menopause, which is the conclusion of menstrual periods, typically around the age of 50.