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: ENT
[{'content': 'The commonest site of aspiration of a foreign body in the supine position is into the: \nSelect and explain. \nA. Right upper lobe apical, B. Right lower lobe apical, C. Left basal, D. Right medial', 'role': 'user'}, {'content': 'Answer: B \nExplanation: In supine position and with the patient on back superior segment of RLL is the most dependent segment.', 'role': 'assistant'}]