This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Misc., Subject name: Pathology
[{'content': 'Oncogene was first identified in \nSelect and explain. \nA. Epstein-Barr Virus, B. Echovirus, C. Adenovirus, D. Retrovirus', 'role': 'user'}, {'content': 'Answer: D \nExplanation: (D) Retrovirus > Cellular Protooncogenes were first discovered in their mutated or "oncogenic" forms as "passengers" within the genome of acute transforming retroviruses by the 1989 Nobel laureates Harold Varmus and Michael Bishop.', 'role': 'assistant'}]