Which of the following surfaces can be used for a pool?

Plaster is a commonly used surface for pools due to its durability, smooth finish, and ability to create a watertight barrier. It is typically applied as a coating over concrete or gunite structures and provides a relatively low-cost option while also being aesthetically pleasing. Plaster surfaces can be easily maintained and repaired, allowing for longevity in swimming pool construction.

Materials like glass, while visually appealing and innovative, are not practical for general pool surfaces due to potential safety issues and high costs. Concrete, while a strong structural component for pools, requires a finishing treatment to make it suitable for swimming, often in the form of plaster or a similar coating. Stainless steel, while chemically resistant and durable, is generally not used as the primary surface for swimming pools due to its high cost and potential for thermal conduction, which could be uncomfortable for users. Thus, plaster stands out as a conventional and effective choice for pool surfacing.