Rna viruses require their own supply of certain enzymes because
a. host cells rapidly destroy the viruses.
b. host cells lack enzymes that can replicate the viral genome.
c. these enzymes translate viral mrna into proteins.
d. these enzymes penetrate host cell membranes.

The correct answer is option b.

Explanation:

RNA viruses have RNA as genetic material whereas the host cells usually have DNA as genetic material.

So, in order to integrate its genome with host DNA, the virus must form DNA from RNA, that is, reverse transcription.

It is the process by which DNA is formed using RNA as a template strand.

However, reverse transcriptase (enzyme which catalyzes reverse transcription) is usually not present in host cells.

Thus, RNA viruses carry their own set of enzymes which help in the replication of viral genome and its recombination with host DNA as host cells lack these enzymes.