To provide hydraulic power to the stabilization system, what should the operator do?

The correct response involves moving the selector valve to the stabilization position to provide hydraulic power to the stabilization system. This action directs the hydraulic fluid to the specific components responsible for stabilizing the aerial device. Stabilization is crucial for safe operation when the device is elevated, as it ensures that the aerial platform remains balanced and reduces the risk of tipping or swaying.

In this context, turning off the main engine would prevent any hydraulic power from being supplied, which is counterproductive for operating the stabilization system. Engaging the parking brakes is focused on securing the vehicle rather than providing hydraulic power. Lowering the aerial device fully might indeed stabilize the device but does not actively engage the hydraulic system for stabilization needed during operation at height. Therefore, moving the selector valve directly impacts the provision of necessary hydraulic power to maintain stability.