To prevent skin irritation near the edges of a cast, the edges should be:

Choosing to petal the edges of a cast is recommended to prevent skin irritation. Petaling involves applying tape or an additional layer of material to the edges of the cast to create a smoother transition between the cast and the skin. This process minimizes the risk of the rough edges of the cast rubbing against the skin, which can cause discomfort, irritation, or even skin breakdown. Proper petaling creates a better fit and enhances the comfort of the cast wearer, allowing for necessary movement while protecting the skin.

While other choices might seem plausible at first glance, they do not effectively address the goal of skin protection and comfort as well as petaling does. For instance, leaving edges rough could lead to increased abrasion against the skin, which is counterproductive. Similarly, folding the edges may not provide the necessary protection and could still result in discomfort. Covering with tape could be beneficial, but without the intentional structuring of petaling, it might not adequately smooth out the interface between the cast and the skin. Thus, the most effective method for preventing skin irritation is to petal the edges of the cast.