Choice A rationale:

Antiviral medications are used to treat viral infections, but tetanus is caused by a bacterium, not a virus. Antiviral medication would not be effective in preventing tetanus.

Choice B rationale:

To prevent tetanus in a person with a puncture wound caused by a rusty nail, providing tetanus antitoxin is essential. The antitoxin can neutralize any tetanus neurotoxin that may have already been produced, preventing its effects on the nervous system.

Choice C rationale:

Wound debridement is the removal of foreign material and dead tissue from a wound, which can help reduce the risk of infection. While important for wound care, it does not specifically prevent tetanus and is not the primary intervention for this case.

Choice D rationale:

Applying a cold compress to the wound can help reduce pain and swelling, but it does not prevent tetanus. The priority is to administer tetanus antitoxin to neutralize the neurotoxin if present.

Choice E rationale:

Anticoagulant therapy is used to prevent or treat blood clotting disorders and is not relevant to preventing tetanus in this scenario.