Which statement accurately describes mandatory signs at airports?

Which statement accurately describes mandatory signs at airports?

• A. Red background with black inscription; denote taxiway centerline.
• B. Green background with white inscription; indicate runway distance remaining.
• C. Red background with white inscription; denote entrance to a runway or critical area and areas where aircraft are prohibited from entering.
• D. Yellow background with black inscription; indicate information only.

Answer: (C)

Mandatory signs convey actions you must follow or areas you must not enter without clearance. They use a red background with white inscriptions, and they mark boundaries such as the entrance to a runway or a critical area, as well as prohibited zones. That’s why this statement is correct: the red background with white inscription identifies a sign that denotes an entry point to a runway or a critical area and areas where entry is prohibited unless authorized. The other color schemes describe different sign types. A red sign with black inscription would not be used for a taxiway centerline—taxiway centerlines are painted on the surface, not signboards. Runway distance remaining signs are not green; they are yellow with black numerals indicating how much runway remains. Yellow signs with black inscriptions are typically information or guidance signs, not mandatory signs.

Mandatory signs convey actions you must follow or areas you must not enter without clearance. They use a red background with white inscriptions, and they mark boundaries such as the entrance to a runway or a critical area, as well as prohibited zones. That’s why this statement is correct: the red background with white inscription identifies a sign that denotes an entry point to a runway or a critical area and areas where entry is prohibited unless authorized.

The other color schemes describe different sign types. A red sign with black inscription would not be used for a taxiway centerline—taxiway centerlines are painted on the surface, not signboards. Runway distance remaining signs are not green; they are yellow with black numerals indicating how much runway remains. Yellow signs with black inscriptions are typically information or guidance signs, not mandatory signs.