Which one is the best explanation of energy?

A. making transformations

B. the ability to do work

C. conservation of power

D. measuring joules

The correct answer is B. the ability to do work

Without energy, there won't be any work done.

Energy is the ability to do work as what science definitions tell us. According to the first law of thermodynamics which is the conservation of energy, energy is neither created nor destroyed but rather just transformed. Among the choices, the best explanation for energy would have to be B.