Why Is Normal Fertilization of One Mature Ovum Usually Performed

Multiple Choice

Why is normal fertilization of one mature ovum usually performed by only one mature sperm even though hundreds of millions of sperm are present in the seminalfluidofone ejaculation?

A) The corona radiata causes the tail of the other sperm to fall off, decreasing their motility.
B) At the time of first penetration, the pH around the ovum changes, and the enzymes of the other sperm are inactivated.
C) Fusion of the two nuclei forms a tight nuclear membrane that prevents the nuclei of other sperm from entering.
D) After being penetrated by one sperm, the ovum's membrane changes electrically and prevents other sperm from entering.