A constituent common to bronze and solder is

Correct answer: tin.

Explanation: Bronze is chiefly an alloy of copper and tin, while common soft solder is typically an alloy of tin and lead (modern lead-free solders are still tin-based). Therefore, the element found in both alloys is tin.

• Lead – in solder but not in bronze.
• Silver – not a standard component of either (except in some specialty solders).
• Copper – in bronze, but not in traditional Sn–Pb solder.
• Tin – present in both bronze and solder. ✅