Which is the most highly developed civilization:Olmec, Maya, Aztec, or inca

Well, out of the 4 only the Mayas are still really a "civilization" in thatl they're not absorbed more or less completely by the modern civilization.

It also depends how you measure development. Maya were the only to develop writing, (this would be my choice if i had to choose) but Inca and Aztecs conquered more land ... In a way, I would say that they were all comparable (the Olmecs however came way before the rest, I wouldn't choose them).