Which antiviral medication is specifically used in the treatment of hepatitis?

Simeprevir is the correct choice as it is specifically designed for the treatment of hepatitis C. This medication is a protease inhibitor that works by interfering with the viral replication process, thus reducing the amount of hepatitis C virus in the body. Simeprevir is often used in combination with other antiviral medications as part of a comprehensive treatment regimen aimed at achieving sustained virologic response, which indicates that the virus is no longer detectable in the blood.

Acyclovir is primarily used to treat infections caused by certain types of viruses, particularly herpes simplex virus and varicella-zoster virus, making it unsuitable for hepatitis treatment. Amantadine is used mainly for influenza A virus and certain types of Parkinson's disease, and it does not have a role in hepatitis management. Oseltamivir, commonly known as Tamiflu, is specifically used for the treatment of influenza, further distinguishing it from the treatment needs of hepatitis patients.

This highlights why Simeprevir is the preferred option among antiviral medications for hepatitis treatment.