The Crossover Point from Radiation to Matter Domination Occurred

Multiple Choice

The crossover point from radiation to matter domination occurred:

A) when the strong force separated from the other two forces.
B) with the emission of the cosmic background radiation.
C) about 50,000 years after the Big Bang, at a temperature of about 16,000 K.
D) with the creation of neutrons and protons, at about 10¹³ K.
E) with the creation of electrons and positrons at about 6 × 10⁹ K.