Which of the following statements regarding the thermal stability and solubility of alkaline earth metal carbonates is correct?

1. A.Thermal stability increases from ${\text{BeCO}}_3$ to ${\text{BaCO}}_3$, while solubility decreases.
2. B.Thermal stability decreases from ${\text{BeCO}}_3$ to ${\text{BaCO}}_3$, while solubility increases.
3. C.Both thermal stability and solubility increase from ${\text{BeCO}}_3$ to ${\text{BaCO}}_3$.
4. D.Both thermal stability and solubility decrease from ${\text{BeCO}}_3$ to ${\text{BaCO}}_3$.