What Is the Main Source of the Energy Radiated by the Sun

What is the main source of the energy radiated by the Sun?

A) Chemical reactions combine hydrogen and helium to produce energy.
B) Protons are destroyed and converted into pure energy as described by Einstein's mass-energy relationship.
C) Small nuclei combine to form larger nuclei with a consequent release of energy.
D) gravitational collapse as described by the Kelvin-Helmholtz contraction