Reverse transcription is formation of cDNA (complementary DNA), double-stranded DNA, from an mRNA template. This is carried out by enzyme reverse transcriptase. Temin and Baltimore discovered enzyme responsible for reverse transcription in two RNA tumour viruses. Accordingly, Rous Sarcoma Virus (RSV) is an RNA retrovirus that is characterized by presence of reverse transcriptase enzyme. This enzyme synsizes DNA using RNA template through reverse transcription. Just after infection, RSV synsizes DNA copies of its genome which n enter nucleus of cell. These viral DNA strands are randomly inserted throughout DNA of host's chromosomes. Now, normal gene transcription within nucleus produces an RSV mRNA which is transferred to cytoplasm. Few copies of viral mRNA are translated  into protein, using machinery of host cell while or becomes incorporated into new virus particles. The correct option is C.