I believe that the answer is C.
The moles of magnesium in 1.25 x 1023 are 20.8 mol.
As the combustible materials burn, some of the chemical energy is transformed into heat energy, and some are transformed into light energy. Light energy, also known as radiation or electromagnetic energy, is a type of kinetic energy that takes the form of visible light waves, such as the light from a match.
In the context of chemistry, yes. Energy input is always equal to the energy output.