Ans. is 'a' Inj. Vitamin B1 .This chronic alcoholic patient is in altered sensorium due to Wernicke's encephalopathy.TreatmentWernicke's disease is a medical emergency and requires immediate administration of thiamine (i.v. or i.m.).Note: That glucose infusion may precipitate Wernicke's disease in a previously unaffected patient or cause a rapid worsening of an early form of the disease.For this reason thiamine should be administered to all alcoholic patients requiring parenteral glucose.