How is it required to mark freight that sticks out from the vehicle’s rear side?

1. With a white flag tied to the tip of the oversize freight.
2. Correct answer: With a red light-reflecting triangle. The length of each triangle side should be 60cm.
3. With a white light-reflecting triangle. The length of each triangle side should be 60cm.
4. With a red flag tied to the tip of the oversize freight.

WhyFreight sticking out at the rear is marked with a red reflective triangle with 60 cm sides. Flags are not enough.