Answer:
D. 1020 J
Step-by-step explanation:
In a closed system the law of conservation of energy is prevalent.
According to the law of conservation of energy "energy is neither created nor destroyed but transformed from one form to another".
- The starting and ending amount of energy must be the same.
- If the system starts with 1020J, then it must end with 1020J
- All the energy transformations will add up to 1020J for the final state.