Having Tracked Her Daily Temperature for Several Months Now,Martha Notices

Multiple Choice

Having tracked her daily temperature for several months now,Martha notices that at one point in her cycle,her temperature dips and then rises as much as a degree.What is she attempting to identify?

A) the point at which ovulation occurs
B) the beginning of the late luteal phase
C) the beginning of menstruation
D) a random temperature variation within a month's time