Final answer:
Puberty is triggered by the secretion of Gonadotropin-releasing hormone (GnRH), which stimulates the release of FSH and LH that in turn stimulate the gonads to produce sex hormones leading to sexual maturity(option a).
Step-by-step explanation:
Puberty is initiated by the secretion of Gonadotropin-releasing hormone (GnRH) from the hypothalamus(option a).
This hormone stimulates the pituitary gland to secrete follicle-stimulating hormone (FSH) and luteinizing hormone (LH), which are key hormones in initiating the changes seen during puberty. In boys, LH stimulates the Leydig cells in the testes to synthesize and secrete testosterone, while FSH stimulates the Sertoli cells. In girls, LH and FSH stimulate the ovaries to produce estrogen, which promotes the growth and development of secondary sex characteristics and reproductive organs.