The nurse receives a new prescription to administer oxygen at 3 L/minute via nasal cannula to maintain an oxygen saturation between 90 and 100% for a client. The nurse obtains an oxygen saturation reading of 85%, and after repositioning the oximeter on a different finger, obtains a second reading of 87%. Which action should the nurse take next?

A Place the client in a Trendelenburg position. C Place the pulse oximeter on the client's earlobe. D Document the second reading in the client's record. B Securely place the prongs of the cannula in the nostrils.