Which component of a chainsaw is responsible for stopping the chain?

The chain brake is a critical safety feature designed to stop the chain's movement almost instantly in the event of kickback or when the operator needs to halt the saw for any reason. When engaged, the chain brake locks the chain in place, preventing any further motion. This component is particularly important for protecting the operator from injury and ensuring that the chainsaw can be handled safely when not in operation.

While the clutch engages and disengages the power from the engine to the chain, it does not stop the chain’s movement by itself. The sprocket is responsible for transferring power from the engine to the chain, facilitating its movement, while the starter mechanism is involved in starting the engine rather than controlling the chain's operation. Therefore, the focused role of the chain brake in stopping the chain makes it the correct and most relevant component in this context.