Final answer:
An increased basal body temperature (Option C) is the best indication that ovulation has occurred. LH levels typically decrease after ovulation, and cervical mucus increases and thins out just before ovulation, providing a predictive measure. Hence, the correct answer is increased basal body temperature.
Step-by-step explanation:
The best indicator that a female is ovulating is an increased basal body temperature (BBT). After ovulation, there is a rise in BBT due to the increased levels of progesterone.
In addition to BBT, ovulation is also characterized by an increase in cervical mucus, which becomes thinner to facilitate the travel of sperm.
Conversely, decreased LH (Luteinizing Hormone) levels typically occur after ovulation during the luteal phase of the menstrual cycle.
Home ovulation predictor kits can measure the surge in LH that precedes ovulation, offering a predictive measure for when ovulation is about to happen.
Therefore, the answer to the question is (Option C) Increased basal body temperature, as this physiological change best signifies that ovulation has taken place.