This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Virology, Subject name: Microbiology
[{'content': 'The only oncogenic virus whose pathogenicity has been proved without doubt is - \nSelect and explain. \nA. HTLV - I, B. HTLV - II, C. HTLV - III, D. HTLV - IV', 'role': 'user'}, {'content': 'Answer: A \nExplanation: HTLV1 present world wide.it causes adult T cell leukemia,tropical dpadtic paraparesid.it mainly infect CD4 cells .infected cell express more inter leukin2 REF:<\\p>MICROBIOLOGY ANANTHA NARAYANAN NINTH EDITION PAGE.567', 'role': 'assistant'}]