A nurse is caring for a child who is having a tonic-clonic seizure and vomiting. Which of the following actions is the nurse's priority?

The correct answer is C: Position the child side-lying. This is the priority action because it helps prevent aspiration of vomit during the seizure, reducing the risk of airway obstruction and potential complications. Loosening restrictive clothing (A) can be done after ensuring the child's safety. Placing a pillow under the child's head (B) is not as critical as ensuring a clear airway. Clearing the area of hazards (D) is important but not the priority during an active seizure.