The Cosmic Microwave Background Radiation Is Not Uniform Over the Sky-It

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