Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): In human females, the lack of menstruation may be indicative of pregnancy. Reason (R): The absence of a menstrual cycle can also be caused by underlying factors such as stress or poor health. In the light of the above statements, choose the most appropriate answer from the options given below:

Step-by-step solution

Assertion (A) is correct because during pregnancy, all events of the menstrual cycle stop and there is no menstruation. Therefore, lack of menstruation is a primary indicator of pregnancy. Reason (R) is also correct because apart from pregnancy, the lack of menstruation can be triggered by environmental or physiological factors such as severe stress or poor health. However, Reason (R) is not the correct explanation for Assertion (A). The correct explanation for Assertion (A) is that after fertilization, the corpus