5. Why do we see a full moon only once every 29.5 days?
A. It takes the moon 29.5 days to rise and set one time.
B. It takes Earth 29.5 days to make one rotation on its axis.
C. It takes Earth 29.5 days to make one revolution around the moon.
D. It takes the moon 29.5 days to make one revolution around Earth.