The best statement of the Law of Conservation of Energy among the provided options is:
The amount of energy put out by a simple machine must equal the amount of energy put into the machine.
However, it's important to note that in real-world applications, due to factors like friction and inefficiencies, the output energy is typically less than the input energy in practical scenarios. Therefore, while the concept of conservation of energy holds true in an ideal system, the statement may need contextual clarification in practical applications.