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': 'Which viral association is found in pityriasis rosea? \nSelect and explain. \nA. HHV 7, B. CMV, C. Varicella Zoster, D. EBV', 'role': 'user'}, {'content': 'Answer: A \nExplanation: The exact etiology of Pityriasis rosea is not known, but it is considered to be a viral disease; Human herpes virus-6 (HHV-6) and human Herpes virus-7 (HHV-7) may play a role.', 'role': 'assistant'}]