What appears as a complete circle in the night sky?

The moon, on the other hand, is very close to Earth, so appears to move relatively quickly across the sky. ... Astronomers measure distances in the sky in degrees, a complete circle being 360 degrees. The moon takes 27.3 days to complete its 360-degree trip around the sky, so moves 13.2 degrees in one night.

the answer your looking for is c. : )