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
Not a cause of hemoptysis - 
Select and explain. 
A. Pneumonia, B. Bronchiectasis, C. Empyema, D. Mitral stenosis
C: Empyema
Answer: C: Empyema 
Explanation: None