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: Microbiology
The following statements are true regarding Clostridium perfringes except : 
Select and explain. 
A. It is the commonest cause of gas gangrene, B. It is normally present in human faeces, C. The principal toxin of C. perfringens is the alpha toxin, D. Gas gangrene producing strains of C. perfringes produces heat resistant spores
D: Gas gangrene producing strains of C. perfringes produces heat resistant spores
Answer: D: Gas gangrene producing strains of C. perfringes produces heat resistant spores 
Explanation: Gas gangrene is caused by Cl perfringens (MC by type A), Cl novyi, Cl septicum, Cl. histolyticum.
Others - Cl. sporogenes, Cl. fullax, Cl. bifermantans, Cl. Sordelli Cl. aerofoetidium and C. tertium.
Most important toxin for gas gangrene is Alpha toxin = lecithinase which is responsible Naegler’s Reaction.
Cl. perfringes is found in feces and contaminates the skin of perineum, buttocks, thigh.
Its spores is used as remote indicator of fecal contamination of water.
Spores are usually destroyed within 5 minutes by boiling but those of food poisoning strains of Type A and certain type C strain resist boiling for several hours.
Spores are destroyed by autoclaving at 121 0 C for 20 minutes.
Spores are resistant to antiseptics and disinfectants in common use.