The Levin tube and the Salem sump tube are used most commonly for stomach decompression. Which of the following statements about these tubes is true? A. Levin tubes have a blue "pigtail" that functions as an air vent. B. These tubes are inserted as a sterile procedure. C. The blue air vent should not be used for irrigation. D. The Salem sump tube has a blue "pigtail" that functions as an air vent. E. The Salem sump is preferred for stomach decompression.