Group I contains parameters and Group-II lists methods/instruments.

$\begin{array}{ll} \textbf{Group I} & \textbf{Group II} \\ P. \text{ Streamflow velocity} & 1. \text{ Anemometer} \\ Q. \text{ Evapo-transpiration rate} & 2. \text{ Penman’s method} \\ R. \text{ Infiltration rate} & 3. \text{ Horton’s method} \\ S. \text{ Wind velocity} & 4. \text{ Current meter} \end{array}$

The $\textbf{CORRECT}$ match of $\textbf{Group I}$ with $\textbf{Group II}$ is

1. $P-1, \: Q-2, \: R-3, \: S-4$
2. $P-4, \: Q-3, \: R-2, \: S-1$
3. $P-4, \: Q-2, \: R-3, \: S-1$
4. $P-1, \: Q-3, \: R-2, \: S-4$