How long should the flag attached to the extension or load of a vehicle be which is carrying a load greater than 1.5 meters?

• 20 centimeters
• 25 centimeters
• 30 centimeters
  Explanation:

  "During daylight hours, a red flag should be attached to the end of the extension or load. The flag must be at least 30 centimeters (one foot) long on each of the four sides of the square."
• 35 centimeters