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': 'Classification of pathogenic streptococci into group A, B, C, D and G is based on - \nSelect and explain. \nA. Color of colonies on blood agar, B. Antigenicity of cell wall carbohydrate, C. Presence or absence of capsule, D. Presence or absence of M protein', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., Antigenicity of cell wall carbohydrate", 'role': 'assistant'}]