Which part of the steering system connects the steering wheel to the gearbox?

Answer: B — Drag link

The drag link is the component in the steering system that connects the steering wheel to the gearbox, facilitating the transfer of motion and direction from the driver's input to the wheels. When you turn the steering wheel, the drag link plays a pivotal role in translating that movement into the necessary adjustments at the gearbox, ultimately allowing the wheels to turn accordingly. This linkage is integral to ensure proper steering response and control, making it essential for safe vehicle operation. The steering arm, while involved in the system, does not directly connect the steering wheel to the gearbox, but rather helps in transmitting the movement to the wheels themselves. The spindle is part of the wheel assembly and is unrelated to the steering connection. The hydraulic fluid reservoir is tied to vehicles with hydraulic steering systems, but it does not directly connect the steering wheel to the gearbox, serving instead as a storage for the hydraulic fluid needed for the steering mechanism's operation.