Final answer:
The nurse should assess the newborn's heart rate and respiratory rate first.
Step-by-step explanation:
The nurse should (b) assess the newborn's heart rate and respiratory rate first. Assessing the heart rate and respiratory rate will provide the nurse with essential information about the newborn's respiratory distress and overall condition. This will guide further interventions, such as auscultating the lungs, suctioning the airway, or administering oxygen, if necessary.