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
Gas gangrene is 
Select and explain. 
A. Caused by Clostridium perfringens., B. Gas and smell are characteristic., C. Antibiotic prophylaxis is essential when performing amputations to remove dead tissue., D. All of the above
D: All of the above
Answer: D: All of the above 
Explanation: None