Which of the Following Is Not an Observed Characteristic of the Cosmic

Which of the following is not an observed characteristic of the cosmic microwave background?

A) It has a perfect thermal radiation spectrum.
B) It contains prominent spectral lines of hydrogen, the primary chemical ingredient of the universe.
C) Its temperature is a little less than 3 Kelvin (3 degrees above absolute zero) .
D) Its temperature is the same everywhere, except for small variations at the level of 1 part in 100,000.