The table shows details about four redox reactions. Which row correctly states what is oxidised and the evidence that this is oxidation?
- AEquation: $\text{CuO}(s) + \text{C}(s) \rightleftharpoons \text{CO}(g) + \text{Cu}(s)$; what is oxidised: copper; evidence: copper oxide has given oxygen to carbon
- BEquation: $\text{Na}(s) + \frac{1}{2}\text{Cl}_2(g) \rightleftharpoons \text{NaCl}(s)$; what is oxidised: sodium; evidence: sodium has lost an electron
- CEquation: $\text{N}_2(g) + 3\text{H}_2(g) \rightleftharpoons 2\text{NH}_3(g)$; what is oxidised: nitrogen; evidence: nitrogen has gained hydrogen
- DEquation: $\text{Zn(NO}_3)_2(aq) + \text{Mg}(s) \rightleftharpoons \text{Mg(NO}_3)_2(aq) + \text{Zn}(s)$; what is oxidised: zinc; evidence: zinc has gained two electrons