1. 8571. High-pressure cylinders containing oxygen for avia tion use can be identified by their A. green color and the words “BREATHING OXYGEN” stenciled in 1-inch white letters. B. yellow color and the words “AVIATOR’S BREATHING OXYGEN” stenciled in 1-inch white letters. C. green color and the words “AVIATOR’S BREATHING OXYGEN” stenciled in 1-inch white letters.