<prompt> Most common oncogenic RNA virus:RetrovirusPicornavirusOrthomyxovirusParamyxovirus  <response>: Ans. is a i.e., Retrovirus Ref: Ananthanarayan, 9the, p. 565 and 8the, p. 563, 565Retroviruses contain an RNA genome and an RNA-directed DNA polymerase reverse transcriptase. Both HIV and HTLV are oncogenic retrovirus. 