How is the cylinder equipped with cushioning according to the symbol?

The correct answer indicates that the cylinder is equipped with an adjustable cushioning device that extends. In hydraulic cylinders, cushioning is crucial for reducing the impact during the end of the cylinder's stroke. This not only enhances the longevity of the cylinder but also ensures smoother operation.

An adjustable cushioning device allows the operator to fine-tune the cushioning effect to meet specific application requirements. This adaptability is beneficial in various environments where load conditions or operational speeds may vary. The ability to adjust the cushioning can prevent abrupt stops and minimize shock loads, which is particularly important in applications with sensitive components or where precision is required.

The other options do not adequately reflect the specific configuration or functionality implied by the question. For instance, a servo positioner serves a different purpose, focusing more on electronic control of position rather than cushioning. A fixed cushioning device lacks the flexibility needed for various operational conditions, while an adjustable device that extends and retracts combines aspects not specified by the original query, leading to a less accurate interpretation of the symbol in question.