In which reaction does the copper compound undergo reduction?
- A$\text{CuCO}_3 \rightarrow \text{CuO} + \text{CO}_2$
- B$\text{CuO} + \text{H}_2\text{SO}_4 \rightarrow \text{CuSO}_4 + \text{H}_2\text{O}$
- C$\text{CuSO}_4 + 2\text{NaOH} \rightarrow \text{Cu(OH)}_2 + \text{Na}_2\text{SO}_4$
- D$2\text{CuO} + \text{C} \rightarrow 2\text{Cu} + \text{CO}_2$