This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory system, Subject name: Medicine
[{'content': 'Platypnea means- \nSelect and explain. \nA. Dyspnea in the supine position and relief in upright position, B. Dyspnea in the upright position with relief in the supine position, C. Dyspena on exeion, D. Dyspnea waking up the patient during deep sleep', 'role': 'user'}, {'content': "Answer: B \nExplanation: Platypnea is defined as dyspnea in the upright position with relief in the supine position.It is seen in left atrial myxoma or hepatopulmonary syndrome. Ref:Harrison's medicine-18th edition,page no:279", 'role': 'assistant'}]