Metals reducible by both carbon and hydrogen from oxides Steps:

• Recall reactivity series: Metals below carbon (Zn, Fe, Cu) reduce with carbon; those below hydrogen (Cu) reduce easily with hydrogen.
• Check carbon reduction: ZnO, Fe2O3, CuO all reduce via C (e.g., 2ZnO + C → 2Zn + CO2).
• Check hydrogen reduction: Only CuO reduces readily with H2 (CuO + H2 → Cu + H2O); Zn and Fe require harsh conditions.
• Eliminate MgO, which needs electrolysis, not C or H2.

Why A is correct:

• Cu is less reactive, allowing reduction by both: CuO + C → Cu + CO (smelting) and CuO + H2 → Cu + H2O (lab method).

Why the others are wrong:

• B. Fe: Reduces with carbon but not easily with hydrogen due to higher reactivity.
• C. Mg: Too reactive; MgO unreactive to both carbon and hydrogen.
• D. Zn: Reduces with carbon but hydrogen reduction is inefficient.

Final answer: A