In a Vasectomy, Each Vas Deferens Is Cut and Sealed

In a vasectomy, each vas deferens is cut and sealed off. This is an effective form of birth control because it

A) prevents sperm formation.
B) prevents semen formation.
C) prevents release of sperm into semen.
D) makes semen too acidic for sperm to function.
E) makes semen too basic for sperm to function.