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: Medicine
[{'content': 'The commonest site for impaction of foreign body in the Gastro Intestinal Tract is \nSelect and explain. \nA. Ileocaecal junction, B. Pyriform fossa, C. Pyloric sphincter, D. Cricopharynx', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]