Who must wait when a driver exits a private driveway and a cyclist approaches from the left?

Answer: B — The driver of the motor vehicle

In this scenario, the driver of the motor vehicle must wait when exiting a private driveway for several reasons rooted in traffic laws and safe driving practices. When a driver is exiting a driveway, they are required to yield to all road users, including cyclists. The cyclist, who is already traveling on the roadway, has the right of way. This principle is critical for maintaining safety, as it prevents potential accidents between the exiting vehicle and the approaching cyclist. Furthermore, yielding is essential to ensure that the cyclist has adequate time and space to maneuver safely past the driveway exit. Since cyclists share the roadway with motor vehicles, drivers need to remain vigilant and respectful of the presence of cyclists, particularly as they approach from the left in this scenario. Recognizing that the cyclist is already on the road reinforces the importance of drivers being patient and cautious when exiting driveways. This practice not only upholds the rules of the road but also promotes a safer environment for all roadway users.