The direct trigger to ovulation seems to be a
a. sharp increase in lh production on approximately day 13 of the menstrual cycle.
b. sharp increase in fsh production on approximately day 13 of the menstrual cycle.
c. sharp increase in progesterone production on approximately day 13 of the menstrual cycle.
d. sharp increase in prolactin production on approximately day 13 of the menstrual cycle.
e. the release of gonadotrophic hormone from the follicle.