What type of brake fluid is typically used in school buses?

Answer: B — DOT 3 or DOT 4 brake fluid

The correct choice is DOT 3 or DOT 4 brake fluid, which is commonly used in school buses. These types of brake fluids are glycol-ether-based and have high boiling points, which is essential for the braking system's reliability and effectiveness, especially under heavy load or when the brakes are used frequently. Their formulation helps prevent vapor lock in the brake lines and maintains braking performance over a wider range of temperatures, which is critical for the safety of a school bus transporting children. This type of fluid also has suitable properties for moisture absorption, ensuring that the fluid maintains its effectiveness over time, even in the presence of moisture. Using DOT 3 or DOT 4 fluid adheres to industry standards for the performance and safety of hydraulic brake systems typically found in school buses.