A nurse is assessing for correct placement of a client's NG feeding tube prior to administering a bolus feeding. Which of the following actions should the nurse take?

A. This is an incorrect action. Inserting air in the tube and listening for gurgling sounds in the epigastric area is not a reliable method to confirm NG tube placement, as it can produce false-positive results due to air entering the stomach or intestines. B. This is a correct action. Aspirating contents from the tube and verifying the pH level is a valid method to confirm NG tube placement, as gastric contents typically have a pH of less than 5.5, while intestinal or respiratory contents have a higher pH. C. This is an incorrect action. Reviewing the medical record for previous x-ray verification of placement is not sufficient to confirm NG tube placement, as the tube can migrate or become dislodged after insertion. X-ray verification should be done initially and whenever there is doubt about the tube's position. D. This is an incorrect action. Auscultating the lungs for adventitious breath sounds is not a specific method to confirm NG tube placement, as it can indicate other conditions such as pneumonia or pulmonary edema. It can also miss signs of respiratory complications due to NG tube misplacement, such as pneumothorax or bronchial obstruction.