Races are described as:

• A. Sliding channels between two sections of the aerial device.
• B. The interior of a box-beam construction aerial device.
• C. The exterior protective covers on the device.
• D. The hydraulic lines inside the arm.

Answer: (A)

Races are the sliding channels between sections of a telescoping aerial device. They are the grooves or tracks that guide the inner boom segments as the boom extends and retracts, keeping everything aligned and allowing smooth, low-friction movement. This focuses on the path the sections follow as they slide past one another, not on the hollow interior of a box-beam, the exterior protective covers, or the hydraulic lines inside the arm.