Which of the Following Statements About the Cosmic Background Radiation

Which of the following statements about the cosmic background radiation is not true?

A) It had a much higher temperature in the past.
B) It was discovered by Penzias and Wilson in the mid- 1960s.
C) It has a temperature of about 3 degrees K above absolute zero.
D) It appears essentially the same in all directions (it is isotropic) .
E) It is the result of a mixture of radiation from many independent sources, such as stars and galaxies that formed within the first billion years of the Big Bang.