In assessing a 2-year-old boy with croup, the practical nurse (PN) finds that he has become increasingly irritable and has developed tachypnea and resting stridor. Which intervention is best for the PN to implement?

A. Administering acetaminophen can help reduce fever and discomfort but does not directly address the respiratory distress indicated by tachypnea and stridor. B. Monitoring the child's oxygen saturation level via pulse oximeter is essential to assess the severity of the respiratory distress. It provides critical information on the child's oxygenation status and helps guide further interventions. C. Encouraging the child to drink adequate amounts of cool, clear liquids is beneficial for hydration but does not directly address the acute respiratory symptoms of irritability, tachypnea, and stridor. D. Instructing the mother to play with the child for stimulation and distraction may help alleviate irritability but does not address the underlying respiratory distress, which requires immediate attention.