Which of the Following Statements Most Accurately Describes the First

Which of the following statements most accurately describes the first law of thermodynamics?

A) one usable form of energy cannot be completely converted into another usable form.
B) one usable form of energy can be completely converted into another usable form.
C) energy cannot be created or destroyed.
D) energy can be neither created nor destroyed but it can be changed from one form to another.
E) energy cannot be transformed.