What Is the Significance of the "Vaginal Code

What is the significance of the "vaginal code?"

A) The pattern of mounts and intromissions ensures that the corpus luteum will be maintained.
B) The pattern of olfactory and visual cues from the male ensures that the female will be vaginally receptive to copulation.
C) It is the chemical signal (pheromone) found on the skin of the vagina that signals males of the appropriate species that the female is in estrus.
D) It is the number of intromissions for a given female that will result in orgasm.