Final answer:
Zidovudine is an antiviral drug effective against viral infections, specifically HIV/AIDS, by inhibiting viral reverse transcriptase.
Step-by-step explanation:
Among the options provided, Zidovudine is sometimes useful against viral infections. Zidovudine is an antiviral drug that was originally approved for the treatment of HIV/AIDS. It works by inhibiting the action of viral reverse transcriptase, which is essential for the replication of retroviruses like HIV. This helps block the replication of the virus within the host cells. Unlike antibiotics, like Trimethoprim and Streptomycin, which are not effective against viruses, certain antiviral medications are specially designed to target viral infections.