The convex mirrors are used to monitor the _________ sides at a _________ angle.

Convex mirrors are specifically designed to provide a wider field of view compared to flat mirrors. This characteristic makes them particularly useful for monitoring the left and right sides of a vehicle, such as a school bus, allowing the driver to see more of the surroundings without having to move their head extensively. The wide angle offered by convex mirrors helps to reduce blind spots, enhancing safety by ensuring that the driver is aware of other vehicles or pedestrians that may not be directly in view.

Using convex mirrors for monitoring the sides at a wide angle is important in driving contexts, especially for larger vehicles, as it facilitates better awareness of surrounding traffic and obstacles. Thus, the option that states convex mirrors are used to monitor the left and right sides at a wide angle is accurate because it highlights their effectiveness in improving visibility and safety on the road. This is why the correct choice emphasizes both the directional aspect (left and right) and the nature of the visibility (wide angle).