What does a triangular road sign with a red border and a gate image warn of?

The correct answer indicates that a triangular road sign with a red border and a gate image specifically warns drivers of a level crossing with a barrier. This type of sign is a crucial safety feature used to alert drivers to the presence of a railway crossing where there is the potential for train operations. The triangular shape captures attention due to its association with warning signs, while the red border signifies caution.

When approaching such a sign, drivers should be vigilant as trains may be approaching, and barriers may come down to prevent road traffic from crossing at dangerous moments. This emphasizes the importance of being aware of and reacting to warning signs in a timely and appropriate manner to ensure safety on the road.