When applying a cast, which of the following materials are considered essential?

The correct answer highlights the essential materials needed for applying a cast effectively. Cotton padding is a crucial component as it provides cushioning and protects the skin underneath the cast. This padding helps prevent skin irritation and pressure sores, which can occur with prolonged cast application.

Water is essential for activating plaster, allowing it to harden and conform properly to the intended shape. The plaster itself is the primary material used in the casting process, providing strength and structural support once it sets.

Saline, while not typically viewed as essential in the casting process, may be included in some medical settings for various purposes, such as cleansing or preparing the skin, but it is not a standard requirement for a cast application.

The other choices contain materials that either do not fulfill the primary purpose of casting or introduce items that are not commonly utilized in standard cast application protocols. By focusing on the requisite materials—cotton padding, water, and plaster—this response affirms the necessary components for providing an effective and safe cast application.