Hydrogen "Burning" in Stars Is ___________

Hydrogen "burning" in stars is ___________.

A) an atomic reaction that fuses 4 protons to make a helium nucleus, releasing energy by converting mass to energy
B) an atomic reaction that generates hydrogen by splitting helium atoms
C) hydrogen atoms that combine with deuterium atoms to make HD complexes, and this reaction generates immense amounts of energy
D) a chemical reaction that bonds hydrogen to oxygen to make water, which remains a gas because of the extremely high temperatures