Match the variable in Group-$1$ with the instruments in Group-$2$.

$\begin{array}{cc}\ &\text{Group-$1$} & \text{Group-$2$} \\ &\text{P. Temperature} & \text{ I. Capacitance probe} \\ &\text{Q. Liquid level} & \text{II. McLeod gauge} \\ &\text{R. Vacuum} & \text{III. Chromatograph } \\ &\text{S. Concentration} & \text{IV. Thermistor} \\ \end{array}$

Choose the correct set of combinations.

1. $P-IV,\:Q-III,\:R-II,\:S-I$
2. $P-I,\:Q-II,\:R-IV,\:S-III$
3. $P-IV,\:Q-I,\:R-II,\:S-III$
4. $P-III,\:Q-II,\:R-I,\:S-IV$