This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Gram-Positive Infections - Corynebacterial Infections, Subject name: Microbiology
[{'content': 'What is the sequence which a retrovirus follows on entering a host cell? \nSelect and explain. \nA. RNA - DNA - RNA, B. RNA - DNA, C. DNA - RNA, D. DNA - RNA - DNA', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., RNA - DNA - RNA(Ref: Ananthanarayan, 9th/e, p. 574 and 8th/e, p. 570)* When HIV infects a cell, the viral RNA is transcribed by reverse transcriptase, first into single stranded DNA and then to double stranded DNA (Provirus).* Provirus is integrated into host cell chromosome.* This provirus initiates viral replication by directing synthesis of viral RNA, in response to viral promoters.", 'role': 'assistant'}]