A nurse is reinforcing teaching with new parents about car seat safety. Which of the following instructions should the nurse include?

A. Incorrect. The airbag should be turned off if an infant car seat is placed in the front seat, as airbags can pose a significant risk to infants. B. Incorrect. The car seat should be positioned at a 45° angle to prevent the infant's head from falling forward and obstructing the airway. C. Incorrect. Placing a small cushion under the newborn's head is not recommended, as it can interfere with proper positioning and safety in the car seat. D. Correct. The shoulder harnesses of the car seat should be positioned at the level of the infant's shoulders to ensure proper fit and safety during travel.