Answer: C. Entecavir
Entecavir is used for the treatment of HBV. It demonstrates activity against HBV, HSV-1, HCMV, VZV in cell lines but has no or little activity against HIV or influenza.
Peramivir is an as-yet-unlicensed neuraminidase inhibitor that is being developed in intravenous and intramuscular formulations.
Fludase (DAS181) is a sialidase fusion construct that cleaves the sialic acid receptors that influenza viruses use for attachment, removing influenza receptors from the airway epithelium and preventing infection of lung cells.
Cyanovirin-N is a hemagglutinin inhibitor that may block viral entry.
T-705 is a substituted pyrazine compound that is active against neuraminidase-inhibitor–resistant and amantadine-resistant viruses and that probably inhibits the RNA polymerase.
Reference
Anne Moscona, M.D.Global Transmission of Oseltamivir-Resistant Influenza. NEJM 360; 10: 953 -956, March 5, 2009 (Weblink here)