This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Clostridium, Subject name: Microbiology
[{'content': "Naegler's reaction is due to which toxin of Cl perfringens - \nSelect and explain. \nA. Alpha toxin, B. Epsilon toxin, C. Kappa toxin, D. Delta toxin", 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Alpha toxin o Naegler's reaction detects alpha toxin (phospholipase or lecithinase C). When Cl. perfringens is grown on a medium with the antitoxin spread on one half of the plate, colonies on the other half without the antitoxin will be surrounded by a zone of opacity. There will be no opacity around the colonies on the half of the plate with the antitoxin, due to the specific neutralisation of the alpha-toxin.", 'role': 'assistant'}]