Which of the following alloys contains 15% zinc?

Red brass is composed primarily of copper and zinc, with the typical alloy containing around 15% zinc. This specific composition contributes to the alloy's strength, corrosion resistance, and castability, which are essential properties in various applications, especially in plumbing and heating systems.

Bronze, on the other hand, is mainly an alloy of copper and tin, and it may contain other elements, but it does not inherently contain zinc as a major component. Stainless steel is primarily an iron alloy enriched with chromium and sometimes nickel, rather than having a significant percentage of zinc. Silicon iron is primarily an iron alloy with silicon, and it doesn't contain a notable amount of zinc either.

Therefore, red brass is the only option that accurately reflects an alloy containing approximately 15% zinc, showcasing its unique properties and suitability for specific industries.