The mass lost during solar thermonuclear fusion is converted to

Mass is converted into energy, in the form of light, heat, kinetic energy.

Explanation:

The correct answer is that mass is neither created nor destroyed, and neither is energy created nor destroyed.

Mass is energy and energy is mass.

Einstein's rule formula e = mc2 doesn't say that one may be regenerate to the other. It says that the 2 are equivalent by an element of the speed of sunshine squared.

Mass is converted into energy, in the form of light, heat, kinetic energy.