What is the role of a ladder's rung?

The role of a ladder's rung is to provide stable footing for the user. Rungs are designed to support the weight of the person using the ladder, allowing them to safely ascend and descend. A well-designed rung ensures that someone can maintain their balance and stability while working at height, which is crucial for preventing accidents and falls.

Although the other choices suggest functions that might seem relevant, they do not align with the primary safety function of a rung. For example, while a good grip can enhance safety, the main purpose of the rungs is not to serve as a grip. Similarly, hanging tools from a rung could lead to imbalance, and the structural integrity of the ladder is dependent on other components, not solely the rungs. Thus, stable footing remains the paramount role of a rung in ladder design.