Answer:
B.
Step-by-step explanation:
Answer A is incorrect because the nurse should be checking to make sure that bubbles are NOT in the humidifier. A is insinuating that there SHOULD be bubbles in the humidifier.
Answers C and D are incorrect because the nursing assistant's job does not entail educating the patient about how to and how not to work the machinery. She is in charge of making sure the patient is getting the oxygen she needs, making sure her tubes are clean, and overall checking the patient's physical health. So the best answer would be B.