Thermonuclear Fusion Reactions in the Core of the Sun Convert

Thermonuclear fusion reactions in the core of the Sun convert four hydrogen nuclei into one helium nucleus. The helium nucleus has:

A) less mass than the four hydrogen nuclei, the lost mass becoming energy in an amount given by E = mc².
B) the same mass as the four hydrogen nuclei, because the mass of any product has to equal the mass of the sum of its parts by the law of conservation of matter.
C) an undetermined amount of mass that depends on the temperature at which the reaction occurs.
D) more mass than the four hydrogen nuclei, because energy is produced in the reaction, and this energy adds the extra mass, m = E/c².