Option (4) is the correct answer because thyrocalcitonin regulates the blood calcium level. Spermatogenesis in human males is regulated by FSH and androgen. Option (1), (2) and (3) are not the correct answer because exophthalmic goitre is a form of hyperthyroidism. Glucocorticoids are secreted by the adrenal cortex. Parathyroid hormone along with TCT, play a significant role in calcium balance in the body.