Law of Conservation of Energy states that

• A. Matter is not created nor destroyed in any chemical or physical change
• B. Energy cannot be created or destroyed in chemical or physical changes
• C. Energy cannot be created or destroyed in any process
• D. Heat energy cannot be transferred

Answer: (A)

Energy cannot be created or destroyed in any process; it can only be transformed or transferred. This means the total amount of energy in a closed system stays the same, even as it changes form—kinetic, potential, chemical, electrical, thermal, and so on.

Think of a swinging pendulum: its energy shifts between potential energy at the top of the swing and kinetic energy as it moves, yet the total energy remains constant. A light bulb converts electrical energy into light and thermal energy, again conserving the total energy. In chemical reactions, chemical energy can become motion or heat, but the sum of all energies doesn't vanish or appear from nowhere.

What’s not correct here is tying energy conservation to matter; that’s a different principle. Saying energy is conserved only in chemical or physical changes is too narrow—energy is conserved in all processes. Heat transfer happening or not doesn’t define conservation either; heat can move, but the energy balance still holds.