The correct answer is option (3)-  A is true but the R is false .

Assertion A is true because viruses having RNA genomes tend to have a shorter lifespan and mutate and evolve faster compared to viruses with DNA genomes. RNA is unstable catalytic molecule .It mutates at a faster rate than DNA . Thus viruses having RNA genome and shorter lifespan ,mutate and evolve faster due to this unstability .

Reason R is incorrect. While it's true that RNA can be relatively unstable compared to DNA, it doesn’t inherently result in slower mutation rates. In fact, the lack of proofreading mechanisms in RNA replication leads to a higher mutation rate, contributing to the rapid evolution of RNA viruses.