What should riders verify about their mirrors before riding?

Answer: B — They are clean and positioned correctly

Before riding, it is essential for riders to ensure that their mirrors are clean and positioned correctly. Clean mirrors provide an unobstructed view of the road and any vehicles behind the rider, which is crucial for making safe decisions while riding. Proper positioning allows the rider to see as much of the lane behind them as possible, minimizing blind spots and enhancing awareness of surrounding traffic. Adjusting mirrors correctly can mean the difference between a safe ride and a potential accident, as it ensures a clear understanding of the traffic situation behind and beside the motorcycle. The other aspects mentioned, such as tinting, factory installation, or advanced features, may be important in different contexts but do not fundamentally impact the immediate safety and visibility a rider needs while on the road.