It would be C the moon because the total of all positions (new moon, first quarter, third quarter, full moon, waxing crescent, waning crescent, waxing gibbous, waning gibbous) of the moon would take about 29.6 days on a regular calendar. I hope this helps. :)
The moon is the closest one on the list. Its period of revolution around the Earth is 27.32 days. (But the length of the cycle of phases, like from one Full Moon to the next one, is 29.53 days.)
