Which statements about the sulphates and carbonates of group V and VI metals are correct?

1. A$\mathrm{CaSO}{}_4$ is more soluble than $\mathrm{SrSO}{}_4$ and $\mathrm{BaSO}{}_4$
2. Bdilute $\mathrm{H}{}_2\mathrm{SO}{}_4$ precipitates $\mathrm{BaSO}{}_4$ immediately from $\mathrm{Ba}{}^{2+}$ solution
3. C$\mathrm{CaCO}{}_3$ suspension dissolves in excess $\mathrm{CO}{}_2$ water as $\mathrm{Ca}(\mathrm{HCO}{}_3){}_2$
4. D$\mathrm{MgSO}{}_4$ is sparingly soluble and precipitates in dilute solution