Ans. (C).Progesterone promotes fertility because its levels rise during ovulation and immediately after.
Progesterone is a female sex-hormone, produced in the ovaries right after ovulation and its level rise immediately after ovulation (as shown in graph). A thick, and proper uterine lining is important for the implantation of zygote in the uterine wall.
Progesterone has the most influence on a secure pregnancy as it promotes the thickening and maintenance of uterine lining. Low levels of progesterone makes it difficult to get pregnant as zygote cannot implant properly.
Thus, the correct answer is option (C).
