Which of these equations are balanced? 1. $\text{Fe}_2\text{O}_3 + 3\text{CO} \rightarrow 2\text{Fe} + 3\text{CO}_2$ 2. $\text{ZnCO}_3 + 2\text{HCl} \rightarrow \text{ZnCl}_2 + \text{CO}_2 + 2\text{H}_2\text{O}$ 3. $\text{Mg(NO}_3)_2 + \text{NaOH} \rightarrow \text{Mg(OH)}_2 + 2\text{NaNO}_3$ 4. $\text{CaCO}_3 + \text{H}_2\text{SO}_4 \rightarrow \text{CaSO}_4 + \text{H}_2\text{O} + \text{CO}_2$
- A1 and 2
- B1 and 4
- C2 and 3
- D3 and 4