When we burn fuels we get :

Combustion is an exothermic chemical reaction in which a fuel reacts with oxygen, breaking and re-forming chemical bonds. This bond-energy change is released to the surroundings as heat (thermal energy) and light (visible radiation) — these are the two direct, primary forms of energy given off by any burning process.

When fuels such as wood, coal, LPG, or petrol are burned, this same combustion reaction takes place: the flame we see is the light energy being emitted, and the warmth we feel near the fire is the heat energy being released. So burning any fuel directly produces heat and light energy together.

Checking the near-miss options against this principle:

• Only light energy — leaves out heat: combustion is exothermic, so a flame always releases warmth along with its glow, never light alone.

• Mechanical and light energy — replaces heat with movement: burning by itself sets nothing into motion; mechanical work appears only indirectly, e.g. inside an engine, not from the combustion reaction alone.

• Light and sound energy — replaces heat with sound: ordinary burning is a quiet process; sound is only produced in special cases such as an explosion, not as a direct output of burning fuel.