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
[{'content': "Elek's gel precipitation test is for - \nSelect and explain. \nA. Gonococcus, B. Diphtheria, C. H. influenza, D. Anthrax", 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., Diphtheria", 'role': 'assistant'}]