Asingle lunar cycle lasts a 1.day2.week3.month4.year

The answer is; 3

A lunar cycle is the phases of the moon as it orbits, once, around the earth (which takes approximately 29.5 days). These phases can be viewed from the earth - new moon to full moon. The light from the sun that hits the moon reflects to the earth. Depending on the position of the moon,  in its orbit, and with respect to a person at a particular position of the earth, the moon will be in a particular phase.