Generally Only One Sperm Fertilizes an Egg Because

Generally only one sperm fertilizes an egg because

A) sperm compete against one another before entering and only the most fit one is accepted.
B) sperm are so few that two are unlikely to arrive at the same time.
C) one small entry hole called the blastopore allows only one sperm to fit through and then seals.
D) many sperm enter but only one set of chromosomes can fuse with the egg nucleus; the other sperm are absorbed.
E) when the first sperm fuses with the egg membrane,it causes the membrane to depolarize and also separates the fertilization membrane and this gap forms a barrier to any other sperm.