Correct Answer - A
Menstrual flow occurs due to the lack of progesterone.
Progesterone is secreted by corpus luteum and is essential for the maintenance of endometrium. This endometrium is responsible for implanation of the festilised is responsible for implanation of the festilised ovum, i.e. pregnancy.
FSH Stimulates gonadal activity and also called as gonadotrophins.
Oxytocin Stimultates contraction in uterus during childbirht.
Vasopressin Stimulate resorption of water and electrolytes by the distal tubules, also called as Antidiuretic Hormone (ADH).