In sheep, reproduction is seasonal and is triggered by changes in day length. During the luteal phase (breeding season), the release of gonadotropin-releasing hormone (GnRH) from the hypothalamus promotes the secretion of gonadotropins that regulate the reproductive cycles of sheep on the cellular level.

Which of the following best explains an advantage of a seasonal increase in these hormones?

a) This surge of hormones will cause advantageous mutations that will be passed onto offspring.

b) Reproducing at a certain time of year increases the number of offspring produced in one birth.

c) Reproducing at a certain time of year is more energy efficient and allows for a better rate of offspring survival.

d) This surge of hormones will produce offspring that are identical to the parents and reduce the risk of genetic disorders.