A solid magnesium compound has the formula $\text{Mg(NO}_3)_2\cdot 6\text{H}_2\text{O}$. If this solid is heated in a hard-glass test-tube, one or more changes may be seen. Which statements are correct?
- A1, 2 and 3 are correct
- B1 and 2 only are correct
- C2 and 3 only are correct
- D1 only is correct