While passing a row of parked cars, you see that there is a driver in one of the parked vehicles. What should you do?

Answer: A — Beep your horn to let the driver know you're there

When passing a row of parked cars and you notice there is a driver in one of the parked vehicles, it is essential to beep your horn to alert the driver of your presence. This action can prevent any sudden movements by the driver, such as opening a door or pulling out into traffic, which could pose a risk to you as a motorcyclist. By using your horn, you are communicating with the driver and creating a safer environment for both of you on the road. The other options are incorrect because changing lanes quickly can be dangerous, speeding up may not leave enough room to react to unexpected situations, and ignoring the driver can lead to potential hazards. Therefore, the best course of action in this situation is to beep your horn to ensure the driver is aware of your presence.