A 2-year-old client returns from surgery after a bowel resection as a result of Hirschsprung's disease. A temporary colostomy is in place. Which immediate postoperative nursing intervention takes priority ？（）
A．Changing the surgical dressing.
B．Suctioning the nasopharynx frequently to remove secretions.
C．Irrigating the colostomy with 100 ml of normal saline solution.
D．Auscultating lung sounds.
