One Piece of Evidence Supporting the Theory of Cosmic Inflation

Multiple Choice

One piece of evidence supporting the theory of cosmic inflation is

A) the observed fact that the temperature of the cosmic background radiation is now about 4 Kelvin.
B) the fact that neutrinos are now known to have no rest mass.
C) the observed fact that the geometry of the universe is "flat.".
D) the observed fact that the geometry of the universe is "open."
E) the fact that neutrinos have been found to have rest mass.