placement of a nasogastric tube

The nurse is checking the placement of a nasogastric tube prior to giving medication and a feeding. Which of the following is the preferred and most accurate method of testing?
A. Insert 5 to 20 mm of air into the tube while listening over the stomach with a stethoscope.
B. Aspirate 20 to 30 ml of gastrointestinal secretions and test the pH.
C. Insert 15 to 20 cc of water into the stomach and listen with the stethoscope.
D. Place an open end of the tube into a glass of water and check for bubbles. GET A GENUINE 100 % CUSTOM TERM PAPER EFFICIENTLY ORDER A 5 STAR COLLEGE TERM PAPER NOW