(d) Copper and Tin
Bronze is an alloy of copper (Cu) and tin (Sn).
Source: Metals and Non-metals, Section 3.5 (Corrosion/Alloys)
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The textbook explicitly states: "bronze, an alloy of copper and tin (Cu and Sn)." Option (a) describes brass (copper + zinc), so students must not confuse the two. Option (c) is a common distractor — bronze contains only Cu and Sn, not zinc. Remembering the pair Brass = Cu+Zn, Bronze = Cu+Sn is a frequent exam tip.