Observe the pictures of a pattern of stars at 8:00 p.m. and again at 6:00 a.m. Why do the patterns of stars appear to move in the sky? (2 points)

a pattern of stars in the bottom left hand corner of the sky

a pattern of stars in the upper left corner of the sky

a
It is caused by the rotation of Earth.

b
It is caused by the stars moving closer to Earth.

c
It is caused by the stars moving at night.

d
It is caused by the sun rotating around Earth.