The following are multiple choice questions (with answers) about medical knowledge.   **Question:** A 65-year-old man comes to the physician because of progressively worsening fatigue for 6 months. During this time, he has also had shortness of breath and palpitations on exertion. He has noticed blood in his stools on three separate occasions in the past 4 months. He has type 2 diabetes mellitus and end-stage renal disease. He drinks two to four beers daily. He does not smoke. His pulse is 95/min and blood pressure is 120/70 mm Hg. Examination shows pale conjunctivae. The abdomen is soft with no organomegaly. Rectal examination is unremarkable. His hemoglobin concentration is 7.2 g/dL, hematocrit is 32%, and mean corpuscular volume is 68 μm3. Which of the following is the most likely underlying cause of this patient's bleeding?   (A) Inflammation in an outpouching of the colonic wall   (B) Symptomatic enlargement of hemorrhoidal plexus   (C) Chronic mucosal and submucosal inflammation of the colon   (D) Arteriovenous malformation in the colonic wall
['(D) Arteriovenous malformation in the colonic wall <> answer', 'The following are multiple choice questions (with answers) about medical knowledge. <> instruction', '(A) Inflammation in an outpouching of the colonic wall \n (B) Symptomatic enlargement of hemorrhoidal plexus \n (C) Chronic mucosal and submucosal inflammation of the colon \n (D) Arteriovenous malformation in the colonic wall <> possible answers', "  A 65-year-old man comes to the physician because of progressively worsening fatigue for 6 months. During this time, he has also had shortness of breath and palpitations on exertion. He has noticed blood in his stools on three separate occasions in the past 4 months. He has type 2 diabetes mellitus and end-stage renal disease. He drinks two to four beers daily. He does not smoke. His pulse is 95/min and blood pressure is 120/70 mm Hg. Examination shows pale conjunctivae. The abdomen is soft with no organomegaly. Rectal examination is unremarkable. His hemoglobin concentration is 7.2 g/dL, hematocrit is 32%, and mean corpuscular volume is 68 μm3. Which of the following is the most likely underlying cause of this patient's bleeding? <> context@"]