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 most common cause of acute cor pulmonale is: \nSelect and explain. \nA. Pneumonia., B. Pulmonary thromboembolism., C. Chronic obstructive pulmonary disease, D. Primary spontaneous pneumothorax', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Answer is B (Pulmonary thromboembolism): Most common causes of acute cor pulmonale is Pulmonary thromboembolism Most common cause of chronic cor pulmonale is Severe COPD', 'role': 'assistant'}]