Match the common name of chemicals in $\text{Group-1}$ with their chemical formulae in $\text{Group-2}$

$\begin{array}{|l|l|l|l|} \hline & \textbf{Group – 1} & & \textbf{Group – 2} \\ \hline P. & \text{Gypsum} & I. & \text{Ca(H$_2$PO}_4)_2 \\ \hline Q & \text{Dolomite} & II & \text{CaSO}_4\cdot 2\text{H$_2$O} \\ \hline R. & \text{Triple superphospate} & III & \text{CaCO}_3 \cdot \text{MgCO}_3 \\ \hline \end{array}$

The correct combination is

1. $\text{P-III, Q-II, R-I}$
2. $\text{P-III, Q-I, R-II}$
3. $\text{P-II, Q-III, R-I}$
4. $\text{P-II, Q-I, R- III}$