How many reflective warning triangles are required for parked vehicles?

Answer: B — Three reflective triangles

For parked vehicles, especially those that may be on a roadway, having three reflective warning triangles is crucial for safety. The presence of these reflective devices ensures that other drivers can see the parked vehicle from a distance, even in low visibility conditions such as at night or in inclement weather. The three triangles should be positioned to create a visual indication of the vehicle's presence, typically one triangle should be placed near the vehicle, and the other two should be set back at appropriate distances to give adequate warning to oncoming traffic. This setup greatly enhances safety by alerting other drivers to exercise caution and potentially change lanes or slow down as they approach.