Catalyzes the formation of N(4)-acetylcytidine (ac(4)C) at the wobble position of elongator tRNA(Met), using acetate and ATP as substrates. First activates an acetate ion to form acetyladenylate (Ac-AMP) and then transfers the acetyl group to tRNA to form ac(4)C34. acetate + ATP + cytidine(34) in elongator tRNA(Met) = AMP + diphosphate + N(4)-acetylcytidine(34) in elongator tRNA(Met) Belongs to the TmcAL family.