Menarche refers to which of the following?

Menarche specifically refers to the onset of menstruation, marking the beginning of a female's reproductive years. It is a significant milestone that typically occurs during adolescence, indicating that the body has reached a stage of maturity where it can begin the menstrual cycle. Understanding menarche is essential in the context of women's health, as it signifies important physiological changes and the start of regular menstrual cycles.

The other options refer to different aspects of the menstrual cycle or reproductive health. For instance, the period of ovulation is a phase in the menstrual cycle when an egg is released from the ovary, which is unrelated to menarche. The highest point in the menstrual cycle typically refers to the peak of hormones like estrogen before ovulation, while the end of menses signifies the conclusion of a menstrual period rather than its beginning. Therefore, menarche is accurately defined as the beginning of menses.