Answer: The correct answer is D. ATP provides energy coupling between exergonic and endergonic reactions.
ATP hydrolysis is an exergonic reaction, as a large amount of energy is released when this molecule is hydrolyzed. ATP is converted into ADP ( adenosine diphosphate) and inorganic phosphate. The energy released in this reaction is utilized by the endergonic reactions ( which require energy) such as photosynthesis.
Thus, the central role that ATP in cellular metabolism is that it provides energy coupling between exergonic and endergonic reactions.