One night, Lissy watched a constellation in the sky over a period of several hours. She found that the constellation seemed to move across the sky. Which of these can explain this?

• A.  Some constellations are moving constellations.
• B.  As the Earth rotates, constellations seem to move.
• C.  The outer portions of the galaxy rotates very slowly around the Earth.
• D.  All constellations move randomly through the sky.