Which action should the nurse implement to ensure accurate oxygen saturation readings via a pulse oximeter?
a. Ensure the patient's hand is warm and well-perfused before placing the pulse oximeter probe
b. Confirm that the pulse oximeter probe is securely and correctly positioned on the patient's finger
c. Verify that the pulse oximeter is properly calibrated and functioning correctly
d. Allow the patient to rest quietly for a few minutes before taking the oxygen saturation reading