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: Surgery
Empyema necessitans is defined as so when - 
Select and explain. 
A. Plural empyema is under pressure, B. Pleural empyema has ruptured into bronchus, C. Pleural empyema has ruptured into the pericardium, D. Pleural empyema is showing extension to the subcutaneous tissue
D: Pleural empyema is showing extension to the subcutaneous tissue
Answer: D: Pleural empyema is showing extension to the subcutaneous tissue 
Explanation: None