This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bacteriology, Subject name: Microbiology
[{'content': 'Gas gangrene is due to \nSelect and explain. \nA. Alpha toxin, B. Theta toxin, C. Beta toxin, D. Delta toxin', 'role': 'user'}, {'content': "Answer: A \nExplanation: The alpha-toxin is produced by all types of Clostridium perfringens and most abundantly by type A strains. This is the most impoant toxin biologically and is responsible for the profound toxemia of gas gangrene. It is lethal, dermonecrotic and hemolytic. It is phospholipids which, in the presence of calcium and magnesium ions, splits lecithin into phosphorylcholine and diglyceride. Reference: Textbook of Microbiology; Anathanarayan and paniker's; 10th edition; Page no: 259", 'role': 'assistant'}]