Based on the Observed Amount of Deuterium in the Universe

Multiple Choice

Based on the observed amount of deuterium in the universe, we can conclude that

A) ordinary (baryonic) matter makes 75 percent of the mass of the universe.
B) neutrons outnumber protons 7 to 1 in the universe.
C) most of the deuterium that was created during the era of nucleosynthesis has since been destroyed.
D) the density of ordinary (baryonic) matter is about 4 percent of the critical density.
E) we live in a critical-density universe.