Choice A rationale:

Initiation of antibiotic therapy is not the primary intervention for severe dehydration in gastroenteritis. Fluid replacement is crucial to correct the fluid and electrolyte imbalances.

Choice B rationale:

Administration of antidiarrheal agents is contraindicated in cases of severe dehydration. These agents can delay the elimination of the causative agent and further worsen fluid loss.

Choice C rationale:

Oral rehydration therapy (ORT) is effective for mild dehydration but may not be sufficient in cases of severe dehydration where oral intake is limited.

Choice D rationale:

Intravenous fluid therapy (IVF) is the appropriate intervention for severe dehydration. IV fluids rapidly restore fluid balance and correct electrolyte imbalances, ensuring timely rehydration and preventing complications.