<prompt> Which of the following antiviral drugs is used against HCV infection?AcyclovirSofosbuvirOseltamivirAdefovir  <response>: Sofosbuvir is a direct acting anti-viral drug used against HCV infection. It is a nucleotide analog that inhibits HCV RNA polymerase NS-5B. The active from of sofosbuvir competes with uridine triphosphate for incorporation into HCV RNA by NS5B polymerase. -Acyclovir: DOC for Herpes simplex virus 1 and 2 and also DOC for varicella zoster -Oseltamivir: DOC for bird flu and swine flu -Adefovir: Primarily used for HBV infection 