input: The following are multiple choice questions (with answers) about medical knowledge.   **Question:** A 75-year-old with hypertension and atrial fibrillation comes to the emergency department because of a 2-hour history of severe abdominal pain and nausea. He has smoked 1 pack of cigarettes daily for the past 45 years. The patient undergoes emergency laparotomy and is found to have dusky discoloration of the hepatic colonic flexure and an adjacent segment of the transverse colon. The most likely cause of his condition is occlusion of a branch of which of the following arteries?   (A) Median sacral artery   (B) Inferior mesenteric artery   (C) Celiac artery   (D) Superior mesenteric artery
output: ['(D) Superior mesenteric artery <> answer', 'The following are multiple choice questions (with answers) about medical knowledge. <> instruction', '(A) Median sacral artery  (B) Inferior mesenteric artery  (C) Celiac artery  (D) Superior mesenteric artery <> possible answers', '  A 75-year-old with hypertension and atrial fibrillation comes to the emergency department because of a 2-hour history of severe abdominal pain and nausea. He has smoked 1 pack of cigarettes daily for the past 45 years. The patient undergoes emergency laparotomy and is found to have dusky discoloration of the hepatic colonic flexure and an adjacent segment of the transverse colon. The most likely cause of his condition is occlusion of a branch of which of the following arteries? <> context']