This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Unknown
[{'content': 'Untrue about 3rd part of duodenum is - \nSelect and explain. \nA. 10 cm in length, B. Derived from foregut, C. Superior mesenteric artery passes anterior to it, D. Lying posterior are inferior vena cava and aorta', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans B', 'role': 'assistant'}]