Match the output signals as obtained from four measuring devices in response to a unit step change in the input signal.

$\begin{array}{cc}\ &\text{P. Gas chromatograph, with a long capillary tube} \\ &\text{Q. Venturi tube} \\ &\text{R. Thermocouple with first order dynamics} \\ &\text{S. Pressure transducer with secondorder dynamics}\\ \\ \end{array}$

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