Final answer:
When towing another vehicle, a red flag must be attached to the chain, rope, or cable to enhance visibility and indicate that there is a tow in progress.
Step-by-step explanation:
When towing another vehicle with a chain, rope, or cable, the law typically requires a red flag to be attached. This is to increase visibility and ensure safety for other road users by signaling that there is a tow in progress. The flag must be of a certain size, usually at least 12 inches square, and should be placed at the halfway point of the tow line to be clearly visible to others on the road. Remember, each state or country may have specific regulations regarding towing, but the red flag is a widely recognized safety measure.