Answer:
The correct answer will be option-D.
Step-by-step explanation:
A virus is the infectious particles which consist of an outer shell made up of capsid proteins which enclose the genetic material of the virus which could be DNA or RNA.
Both DNA and RNA virus are pathogenic and certain antiviral vaccines which control the spread of disease. The target of these vaccines is the genetic material as they act by disturbing the enzyme complexes of replication, transcription and translation.
The vaccines need to be revised for the flu virus as the virus contains RNA as their genetic material which has the ability to mutate very easily as they were evolved during the time when the environment was unstable.
Thus, option-D is the correct answer.