A 46-year-old man presents to your office because of the recent onset of blackouts. He has no past medical history and admits to smoking cigarettes and drinking beer socially more recently since his divorce. His blackouts usually occur on weekends, when he is out with his friends relaxing at the neighborhood bar. His physical examination is normal. Which of the following is the next best diagnostic step for this patient? a. CAGE questionnaire b. Liver function tests c. Percussion of the liver for hepatomegaly d. Mini-mental status examination (MMSE) e. Check for macrocytic anemia