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': 'While inserting a central venous catheter, a patient develops respiratory distress. The most likely cause is - \nSelect and explain. \nA. Hemothorax, B. Pneumothorax, C. Pleural effusion, D. Hypovolumia', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]