Match Column $(A)$ with the appropriate options in Column $(B)$.

Column $(A)$	Column $(B)$
$(a)$ $BeO$	$(p)$ Amphoteric
$(b)$ $MgCO_3 \cdot CaCO_3$	$(q)$ Dolomite
$(c)$ $BeCl_2$	$(r)$ Covalent
$(d)$ $Al(OH)_3$	$(s)$ Basic

Given below are two statements: One is labelled as Assertion $A$ and the other is labelled as Reason $R$ :
Assertion $(A)$ : $BeCl_2$ and $MgCl_2$ produce characteristic flame.
Reason $(R)$ : The excitation energy is high in $BeCl_2$ and $MgCl_2$.
In the light of the above statements,choose the correct answer from the option given below :

The correct order of decomposition temperature of $MgCO_3$ $(X)$,$BaCO_3$ $(Y)$,$CaCO_3$ $(Z)$ is

Which of the following metals belong to the same group in the periodic table?

The most abundant metal ion present in the human body is

The order of thermal stability of carbonates of $IIA$ group is