When copper(II) carbonate is heated, it breaks down into copper(II) oxide and carbon dioxide. If the copper(II) oxide produced is then heated with carbon, copper is formed. What colour changes are seen in these reactions?
- Agreen $\rightarrow$ black $\rightarrow$ brown
- Bgreen $\rightarrow$ white $\rightarrow$ brown
- Cblue $\rightarrow$ black $\rightarrow$ silver
- Dblue $\rightarrow$ white $\rightarrow$ brown