In engineering materials, brass is the alloy formed from which metals? Choose the single correct pair.

Introduction / Context:
Recognizing common industrial alloys is essential for specifying fittings, fasteners, and architectural hardware. Brass and bronze are frequently confused, yet their compositions and properties differ meaningfully for corrosion behavior and machinability.

Given Data / Assumptions:

• We are identifying the principal alloying pair only.
• Minor additions (lead, tin) are ignored for the definition.

Concept / Approach:

Brass is primarily copper + zinc. Varying Zn content tunes strength and color; free-cutting brasses may contain a little lead for machinability, but the defining pair remains Cu–Zn. By contrast, bronzes are copper + tin (and sometimes other elements), and other pairs listed do not define brass.

Step-by-Step Solution:

Verification / Alternative check:

Standards for brass compositions (e.g., IS/ASTM) list copper and zinc as the major elements.

Why Other Options Are Wrong:

Zinc–lead and zinc–nickel describe other alloy types; tin–silver and tin–lead relate to solders, not brass.

Common Pitfalls:

Confusing brass with bronze (Cu–Sn); remember: brass = Cu + Zn and bronze = Cu + Sn.

Final Answer:

Copper and zinc