The correct option is A Production of plasma of semen, protection and nourishment of sperm
The function of prostate gland is to secrete a slightly alkaline fluid, milky or white in appearance, which protects the sperm from the acidic environment in female vaginal tract. Also, provide nourishment and energy to the sperm.
Seminal vesicles secrete a significant proportion of the fluid that ultimately becomes the semen when mixed with sperm.
Thus, the correct answer is option A.