Which of the following is NOT a component of the crane's upper-works?

The correct choice identifies outriggers as not being a component of the crane's upper works. The upper works of a crane primarily consist of components that are mounted on the turntable and facilitate lifting and maneuvering operations. This includes the engine, which provides the necessary power for operation; the turntable itself, which allows for rotation; and the hoist mechanism, which is directly involved in lifting and lowering loads.

In contrast, outriggers are part of the crane's lower structure and are used to stabilize the crane during operations by extending outward. They do not play a role in the functioning aspects of the upper works, making this distinction crucial for understanding the structural components of a crane.