Most Cells Use a Tremendous Amount of ATP

Most cells use a tremendous amount of ATP,

A) so our bodies therefore produce and maintain a huge amount of ATP in storage.
B) but only a little ATP is needed because it is an enzyme and does not participate in a reaction.
C) but the amount of stored ATP is not great because our body constantly generates ATP from ADP + P.
D) mainly because ATP is not very efficient as an energy currency.
E) but only for chemical work; transport and mechanical work must use transport and mechanical molecules.