Which of the following has minimum MAC ?
Methoxyflurane has minimum MAC and is most potent. Order of potency in decreasing order (MAC in increasing order) :-

Methoxyflurone (MAC= 0.16%)> Trilene (0.2%) > Halothane (0.74%) > Chloroform (0.8%) > Isoflurane (1.15%) > Enflurane (1.68%) > Ether (1.92%) > Sevoflurane (2.0%) > Desflurane (6.0%) > Cyclopropane (9.2%) > N20 (104%).
Methoxyflurane
N2O
Halothane
Desflurane