The Central Dogma Has Been Challenged on Several Levels (E

The central dogma has been challenged on several levels (e.g. ,the discovery of RNA viruses,which use their RNA to directly synthesize proteins;and the discovery of reverse transcriptase,which makes DNA from RNA) .Which of the following is another example of an exception to the central dogma?

A) DNA from viruses can insert themselves into host cell chromosomes.
B) Chaperone molecules guide the folding of protein molecules.
C) Gene mutations result in altered amino acid sequences of proteins.
D) Prions are infectious protein molecules capable of altering the folding of normal proteins.