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Read the passage given below and answer the following questions.

The testes are primary sex organ and situated outside the abdominal cavity within a pouch called scrotum. The scrotum helps in maintaining the low temperature of the testes, i.e. \[2-2.5\text{ }{}^\circ C\] lower than the normal internal body temperature necessary for spermatogenesis, i.e. sperm formation. In adults, each testis is oval in shape, with a length of about 4 to 5 cm and a width of about 2 to 3 cm. The testis is covered by a dense covering. Each testis has about 250 compartments called testicular lobules. Each lobule contains one to three highly coiled seminiferous tubules in which sperms are produced. Each seminiferous tubule is lined on its inside by two types A cells called male germ cells or spermatogonia and Sertoli cells of columnar shape. The male germ cells are cuboidal in shape and undergo meiotic divisions finally leading to sperm formation, while Sertoli cells provide nutrition to the germ cells. The regions outside the seminiferous tubules called interstitial spaces, contain small blood vessels and interstitial cells or Ley dig cells. Leydig cells synthesise and secrete testicular hormones called androgens, e.g. testosterone. Other immunologically competent cells are also present.

The human testes are

A) Primary sex organ

B) Secondary sex organ

C) Tertiary sex organ

D) Accessory sex organ