Ans. d. Creatine phosphate.The high group transfer potential of ATP enables it to act as a donor of high-energy phosphate compounds. There are three major sources of high phosphate compounds taking pa in energy conservation i.e. oxidative phosphorylation, glycolysis, and citric acid cycle.Phosphagens act as storage forms of group transfer potential and include creatine phosphate, which occurs in veebrate skeletal muscle, hea, spermatozoa, and brain, and arginine phosphate, which occurs in the inveebrate muscle.