This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Pleural effusion & Pulmonary alveolar proteinosis, Subject name: Medicine
[{'content': 'What is the indication for therapeutic thoracocentesis? \nSelect and explain. \nA. Free fluid separates the lung from chest wall by 10 mm, B. Loculated pleural fluid, C. Recurrence of pleural fluid < 72 hours of previous thoracocentesis, D. Mesothelioma', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Therapeutic thoracocentesis- Indication - Free fluid separates the lung from chest wall by 10 mm Measured radiographically Preferred site of thoracocentesis -7th ICS Scapular line. For Recurrent pleural effusion - pleurodesis. In pleurodesis we inject a sclerosing agent in pleural space which causes obliteration of pleural cavity', 'role': 'assistant'}]