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: Dental
[{'content': "All of them are usually seen as an opportunistic infection in AIDS except: \nSelect and explain. \nA. Candidiasis, B. Kaposi's sarcoma, C. Rubella, D. Cytomegalovirus infection", 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]