The best statement of the Law of Conservation of Energy from the provided options is:
The amount of energy put out by a simple machine must equal the amount of energy put into the machine.
This statement accurately reflects the principle that energy cannot be created or destroyed, only transformed from one form to another, meaning the total energy input will equal the total energy output, accounting for losses due to inefficiencies. However, in practical applications like simple machines, the output energy is often less than the input energy due to these inefficiencies.