Which statement about closed or nonoperational runway markings is true?

• A. They are yellow with no retroreflective properties
• B. They are Xs with arms at least 20 ft wide by 50 ft long
• C. They are Xs with arms at least 10 ft wide by 60 ft long
• D. They are Xs with arms 20 ft wide by 60 ft long

Answer: (C)

When a runway is closed or nonoperational, the marking used is a large X across the runway to clearly signal that it is not available. The key detail here is the size of the X's arms. The standard requires each diagonal arm to be at least 10 feet wide and 60 feet long, which makes the mark large enough to be seen from a distance and recognizable regardless of runway size. The color is typically yellow to indicate temporary closure, but the defining feature in this context is the specific dimensions of the X. Other options either give incorrect dimensions or focus on color alone, which doesn’t identify the marking’s required size.