How Was the "Deuterium Bottleneck" Removed So That Helium Could

How was the "deuterium bottleneck" removed so that helium could form?

A) With the formation of the first stars, nucleosynthesis had a confined, uninterrupted space in which to produce both deuterium and hydrogen.
B) The formation of deuterium requires the strong force, and this did not separate out from the other forces until sometime after the cosmic singularity. When it did, the deuterium bottleneck ended.
C) As the universe expanded, its photons cooled, lost energy, and eventually became unable to disrupt deuterium.
D) As the universe expanded, the protons and neutrons cooled, lost energy, and were eventually able to stick together without bouncing apart.