What Are the Factors That Explain Why a Woman Is

What are the factors that explain why a woman is fertile only a few days out of each monthly cycle?

A) (1) Sperm usually cannot survive in the female reproductive tract for more than a few days, (2) an ovum must unite with a sperm during the first 24 hours after ovulation, before it reaches the uterus, so it will be ready for implantation, and (3) the cyclical mechanisms of female reproductive function limit the release of ova.
B) (1) Sperm usually cannot survive in the female reproductive tract for more than 24 hours, (2) an ovum must unite with a sperm within the first 12 hours after ovulation, before it reaches the uterus, so it will be ready for implantation, and (3) the cyclical mechanisms of female reproductive function limit the release of ova.
C) (1) Sperm usually cannot survive in the female reproductive tract for more than a few days, (2) an ovum must unite with a sperm within 12 hours after ovulation, before it reaches the uterus, so it will be ready for implantation, and (3) the cyclical mechanisms of female reproductive function limit the release of ova.
D) (1) Sperm usually cannot survive in the female reproductive tract for more than 12 hours, (2) an ovum must unite with a sperm immediately after ovulation, before it reaches the uterus, so it will be ready for implantation, and (3) the cyclical mechanisms of female reproductive function limit the release of ova.