This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Breast, Subject name: Surgery
Retromammary abcess arises from: 
Select and explain. 
A. Tuberculous rib, B. Infected haematoma, C. Chronic empyema, D. All of the above
D: All of the above
Answer: D: All of the above 
Explanation: Ans: d (All of the above)Ref: Still searching