The equations show two reactions, P and Q, involving lime (calcium oxide). P: $\text{CaO} + \text{SiO}_2 \rightarrow \text{CaSiO}_3$ Q: $\text{CaO} + \text{SO}_2 \rightarrow \text{CaSO}_3$ During which processes do these reactions take place?
- AP: extraction of iron; Q: extraction of iron
- BP: extraction of iron; Q: flue gas desulfurisation
- CP: flue gas desulfurisation; Q: extraction of iron
- DP: flue gas desulfurisation; Q: flue gas desulfurisation