The male secretory structures that produce a fluid necessary for adequate sperm motility after ejaculation are called the:

seminal vesicles and prostate gland

seminal vesicles are a pair of gland located behind the bladder, over the prostate gland (a walnut-sized gland located between the bladder and the penis) and opposite the rectum. seminal vesicles and prostate gland produces a fluid which feeds the sperm and this fluid has clotting ability that makes the semen sticky. this makes sure that the semen clings inside the vagina for a long time to allow the sperm to travel to the egg with ease.

c is the correct answer!