Which of the following materials is acceptable for making the information sign?

The correct answer indicates that either rigid plastic or metal is an acceptable material for making the information sign in the context of NFPA 25. This is important because the information signs used in fire protection systems need to be durable, weather-resistant, and easily readable to ensure that they convey critical information effectively. Rigid plastic and metal are both materials known for their strength and longevity, making them suitable for signs that must withstand environmental conditions, as well as the potential wear and tear they may encounter in various settings.

In contrast, although plywood and glass could theoretically be used for signage, they do not offer the same level of durability or practicality in many fire protection environments. Plywood may be prone to moisture damage and deterioration over time, while glass, despite being a sturdy material, poses safety risks if broken and may not be as easily legible in certain conditions. Rubber, on the other hand, is not typically used for signs because it lacks the rigidity and structure needed for clear visibility and durability in a fire protection context. Therefore, the choice of rigid plastic or metal aligns with the standards for visibility, safety, and longevity required by NFPA guidelines.