Which is not the male sex accessory gland?

The correct answer is Option (3) → Rete testis

Option (1) Seminal vesicle — A male accessory gland. The seminal vesicles are paired glands. Their secretion forms part of the seminal plasma, which is rich in fructose, calcium and certain enzymes.

Option (2) Prostate — A male accessory gland. The prostate is a single gland around the urethra. Its secretion is also part of the seminal plasma.

Option (3) Rete testis — Not a male accessory gland. The rete testis is a duct, not a gland. It is the first of the male sex accessory ducts: rete testis, vasa efferentia, epididymis and vas deferens. These ducts store the sperms and carry them from the seminiferous tubules to the outside.

Option (4) Bulbourethral gland — A male accessory gland. The paired bulbourethral glands secrete a fluid that helps in the lubrication of the penis.

NCERT Extract:
The Male Reproductive System – “… The male sex accessory ducts include rete testis, vasa efferentia, epididymis and vas deferens (Figure 2.1b). The seminiferous tubules of the testis open into the vasa efferentia through rete testis.”
The Male Reproductive System – “The male accessory glands (Figure 2.1a, b) include paired seminal vesicles, a prostate and paired bulbourethral glands. Secretions of these glands constitute the seminal plasma which is rich in fructose, calcium and certain enzymes. The secretions of bulbourethral glands also helps in the lubrication of the penis.”