Which of the following statements are correct regarding the female reproductive cycle?
A. In non-primate mammals, cyclical changes during reproduction are called the oestrous cycle.
B. The first menstrual cycle begins at puberty and is called menopause.
C. Lack of menstruation may be indicative of pregnancy.
D. Cyclic menstruation extends between menarche and menopause.
Choose the most appropriate answer from the options given below: