Rigid metal conduit can be made from which of the following materials?

Rigid metal conduit is specifically designed to provide long-lasting durability, protection, and support for electrical circuits, and it is primarily made from metals. The correct materials listed in choice B—stainless steel and red brass—are both suitable for making rigid metal conduit due to their strength, resistance to corrosion, and ability to withstand harsh environmental conditions.

Stainless steel is often chosen for its excellent resistance to oxidation and corrosion, making it ideal for use in both industrial and marine environments. Red brass, which is an alloy of copper, zinc, and a small amount of lead, also offers good resistance to corrosion and is strong, allowing it to safely house electrical wiring.

Other options include materials such as plastic (commonly used in non-metallic conduit systems) and PVC, which do not classify as rigid metal conduit but rather serve different purposes or applications in electrical installations. Hence, they are not appropriate for this context.