Most common oncogenic RNA virus:
High-Yield Explanation
Ans. is 'a' i.e., Retrovirus (Ref: Ananthanarayan, 9th/e, p. 565 and 8th/e, p. 563, 565)Retroviruses contain an RNA genome and an RNA-directed DNA polymerase (reverse transcriptase). Both HIV and HTLV are oncogenic retrovirus.