The main function of male gonads is to produce gametes and hormones. In males, the gonads are called testes and they produce sperm cells (male gametes) and hormones like testosterone. The hormones produced by gonads give rise to secondary sexual characteristics like beards in men.
Vas deferens (B) is the duct which conveys sperm cells from the testicle to the urethra.
Ejaculatory ducts (C) are formed by the union of vas deferens with the duct of the seminal vesicle. They pass through the prostate and open into the urethra.
Bulbourethral glands (D) are exocrine glands located beneath the prostate gland. They serve to protect the sperm cells during ejaculation.
Therefore, the options B, C & D are incorrect because they do not play direct roles in sperm cell development.
Spermatozoa develop within Seminiferous tubules (A) of each testis. They are the locations of meiosis and the subsequent creation of sperm cells. The epithelium of the tubule has Sertoli cells which are columnar type cells. Initially, spermatogonal stem cells give spermatogonia and these give primary spermatocytes by mitosis, which mature into spermatozoa.
Therefore, option (A) is correct.