Sperm Cannot Fertilize an Ovum Unless It Has Been in the Female

Sperm cannot fertilize an ovum unless it has been in the female reproductive tract for several hours. This enhanced ability of the sperm to fertilize the ovum is called capacitation. In vitro studies indicate that freshly ejaculated sperm can fertilize the ovum if they are first rinsed in salt solution before being introduced to the ovum. These observations suggest that

A) the process of capacitation involves the removal of some inhibiting substances from the sperm.
B) the process of capacitation is temperature dependent.
C) in capacitation, secretions of the female reproductive tract are taken up by the sperm.
D) pH is an important factor in the process of capacitation.
E) only sperm that come into contact with vaginal secretions are capable of fertilizing an ovum.