The Cosmic Microwave Background Radiation Is Not Uniform Over the Sky

Multiple Choice

The cosmic microwave background radiation is not uniform over the sky: It is slightly hotter toward the constellation Leo and slightly cooler in the opposite direction toward Aquarius.Why?

A) The background radiation really is uniform;the observed difference is due to Earth's motion through the universe.
B) That is the way the universe began: hotter in one direction and cooler in the other.
C) The difference is probably a statistical fluctuation,and therefore not real.
D) Earth is slightly off-center in the universe,so one side of the universe is a bit closer and the other side is a bit farther away.