Which of the following is the best definition of energy? (points : 1)
the ability to generate electricity

the ability to generate heat

the ability to do work

the ability to produce fusion

Energy is best defined as "the ability to do work". This is the fundamental definition of energy which has been used by physicists for a very long time, and highlights the most important definitional property of energy - be it kinetic or potential - the capability to do work on objects by causing them to move.

If you want the answer you need to post the figure above that it's talking about and you