What type of sign warns you that the highest safe speed for an upcoming turn is 25 mph?

The correct response is advisory speed sign because this type of sign is specifically designed to indicate the maximum safe speed for navigating a turn or curve. Advisory speed signs are used to provide guidance to drivers about the appropriate speed under optimal driving conditions, ensuring safety while navigating potentially hazardous roadway features, such as sharp turns. These signs are especially important in areas where the road's geometry might require drivers to adjust their speed to maintain control of their vehicles.

In contrast, warning signs typically indicate a potential hazard on the road ahead, but they do not specify a safe speed. No speed limit signs would be used to indicate that there are no restrictions on speed in that area, and turn restriction signs communicate restrictions regarding the direction you can travel but do not provide information about safe speeds for turns. Each of these other types of signs serves a different purpose and does not convey the specific information about safe speeds that an advisory speed sign does.