Which of the following instructions should the nurse include?

The correct answer is A: Keep the car seat in a rear-facing position until your infant is 2 years old. This instruction is crucial for infant safety as rear-facing car seats provide the best protection in case of a crash, especially for infants under 2 years old. It helps to support the infant's head, neck, and spine alignment, reducing the risk of injury. Choices B, C, and D are incorrect. B is unsafe as the harness should be fastened snugly against the infant's body without any bulky clothing like a winter coat. C is incorrect as airbags can pose a serious threat to infants and should be deactivated if the car seat is placed in the front passenger seat. D is also wrong as padding the backrest with a thick blanket can compromise the effectiveness of the car seat in a crash.