The answer is B) ATP + oxygen --> ADP + P
Adenosine triphosphate (ATP) is the energy currency stored in every living cell. ATP is a complex molecule which composed of the nucleoside adenosine and a tail of three phosphates. Normally energy is released from the ATP molecule by a reaction that removes one of the phosphate-oxygen groups and becomes adenosine diphosphate (ADP). Thus, ATP converts to ADP to liberate energy. ADP soon after release, it is recharged in the mitochondria and comes out again as ATP.