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: Anaesthesia
Heimilch valve is used for drainage of: 
Select and explain. 
A. Pneumothorax, B. Hemothorax, C. Empyema, D. Malignant pleural effusion
A: Pneumothorax
Answer: A: Pneumothorax 
Explanation: Pneumothorax