Describe the function of a coolant recovery tank in a school bus.

Answer: B — To collect overflow coolant

The coolant recovery tank in a school bus plays a crucial role in managing the vehicle's cooling system. Its primary function is to collect overflow coolant that may escape from the radiator during system operations, especially when the engine temperature increases and causes the coolant to expand. When the engine cools down, the cooled coolant is drawn back into the radiator from the recovery tank, ensuring a consistent coolant level and preventing low levels that could cause overheating. This is important for maintaining optimal engine operating temperatures, preventing damage, and ensuring efficient function of the cooling system. By effectively managing the coolant levels, the recovery tank contributes to the overall reliability and longevity of the engine and cooling components. The other options listed relate to different systems and functions within the bus that are not associated with coolant management, highlighting the specific purpose of the recovery tank.