Why is it generally harder to achieve selective toxicity for antiviral drugs than for antibacterial drugs?

• A. Antibiotics face less immune interference since bacterial infections are extracellular, while antiviral drugs cannot be delivered systemically due to immediate neutralization by antibodies.
• B. Viruses replicate inside host cells and use many host enzymes and pathways, so viral-specific targets are fewer and often similar to host components.
• C. Antiviral compounds are rapidly metabolized by the liver more than antibiotics, which makes maintaining selective levels in tissues impossible with current pharmacology.
• D. Because viruses are larger than bacteria and physically shield their proteins from drugs, making it more difficult for small molecules to reach viral enzymes.

Answer: (B)