This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Systemic Bacteriology (Gram Positive Bacilli, Gram Negative Bacilli), Subject name: Microbiology
Which is the most common causative agent of gas gangrene? 
Select and explain. 
A. Cl. histolyticum, B. Cl. novyi, C. Cl. septicum, D. Cl. perfringens
D: Cl. perfringens
Answer: D: Cl. perfringens 
Explanation: Clostridium perfringens is the most common causative agent of gas gangrene. Gas gangrene: Established agents: C. perfringens (Most Common, 60-80%) and C. novyi and C. septicum (20-40%). Probable agents: C. histolyticum, C. sporogenes, C. fallax, C. bifermentans, C. sordellii, C. aerofoetidum and C. teium.