38. The enzymatic oxidation of ethanol to acetaldehyde in human body is a zeroth-order reaction: The blood alcohol concentration (BAC) of a man who drank some wine drops from 120 mg/dL to 60 mg/dL within 2.0 hours. How much time is required for his BAC drops from 60 mg/dL to 30 mg/dL? (A) 45 min (B) 1.0 hour (C) 2.0 hours (D) 3.3 hours (E) 4.0 hours