What is a “warning sign” in driving?

Answer: B — sign that indicates upcoming hazards that require caution

A "warning sign" in driving is specifically designed to alert drivers to upcoming hazards that may require caution. These signs typically signal potential dangers on the road, such as sharp turns, pedestrian crossings, or changes in road conditions. The purpose of these signs is to provide drivers with advance notification so they can adjust their speed and driving behavior accordingly to ensure safety. While speed limit signs indicate the maximum legal speed, and parking rule signs specify where and when drivers can park, these do not serve the same purpose as warning signs. Signs indicating service areas provide information about nearby services but do not alert drivers to immediate hazards. Thus, understanding that warning signs are primarily about caution and awareness of potential dangers is essential for safe driving.