A 55-year-old man with a 20-year history of alcohol use disorder completes a 30-day inpatient rehabilitation program. Six months later, he maintains continuous abstinence verified by urine ethyl glucuronide testing and regular counseling sessions. However, he reports experiencing intense cravings, particularly in social situations, and expresses concern about relapse risk. Vital signs are stable. Laboratory studies show AST 68 U/L and ALT 55 U/L (mild hepatic transaminitis), with normal bilirubin and albumin. His hepatitis C and B serologies are negative. His psychiatrist prescribes naltrexone as an adjunct to his ongoing psychosocial treatment. Which of the following best explains the mechanism by which naltrexone reduces relapse risk in alcohol use disorder?

1. A)Antagonism of mu opioid receptors decreases the rewarding effects of alcohol-induced dopamine releaseGABARITO
2. B)Inhibition of aldehyde dehydrogenase produces an aversive reaction similar to disulfiram when alcohol is consumed
3. C)Enhancement of GABA-ergic inhibitory neurotransmission reduces craving and withdrawal symptoms
4. D)Blockade of alcohol dehydrogenase prevents the conversion of ethanol to acetaldehyde
5. E)Stabilization of glutamate-mediated excitatory activity restores normal cortical reward processing