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
Which viral association is found in pityriasis rosea? 
Select and explain. 
A. HHV 7, B. CMV, C. Varicella Zoster, D. EBV
A: HHV 7
Answer: A: HHV 7 
Explanation: 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.