Which Statement Best Describes How the Interconversion of ATP and ADP

Which statement best describes how the interconversion of ATP and ADP is responsible for storing and providing energy for cellular reactions?

A) The energy required to phosphorylate ADP is stored in ATP, and released when ATP undergoes hydrolysis.
B) The energy required to hydrolyze ATP comes from the energy producing reactions in the cell; the energy lost is then stored in ATP.
C) The energy stored in ADP is released when ATP is synthesized.
D) The energy released in the phosphorylation of ADP can be coupled with unfavorable reactions within the cell.