Which statement regarding atp is false?

(a) atp can act as a group donor in adenylylation reactions.
(b) most enzymes that use atp bind it in a form complexed with mg2+.
(c) atp concentrations in a cell are usually much higher than the equilibrium concentration for atp hydrolysis.
(d) compared with other phosphate‑containing compounds in biochemistry, atp has a higher free energy than nearly all of the others.