What is the mechanism of action of Carbamazepine?

Carbamazepine (used for epilepsy, trigeminal neuralgia, bipolar disorder) acts by ENHANCING INACTIVATION OF VOLTAGE-GATED SODIUM CHANNELS — specifically it reduces HIGH-FREQUENCY REPETITIVE FIRING of action potentials by stabilizing sodium channels in their inactivated state. This prevents seizure propagation. It's similar to phenytoin in MOA. It is NOT a GABA agonist (benzodiazepines/barbiturates do that), calcium channel blocker (ethosuximide/gabapentin), or NMDA antagonist (ketamine/nitrous oxide). A is correct.