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: Medicine
[{'content': 'Best diagnostic modality for rotavirus diarrhea \nSelect and explain. \nA. Isolation virus from stool culture, B. Detection of antigen in serum, C. Detection of antigen in stool, D. Detection of antibody in serum', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]