Match correctly for method of drilling given in column A to principle of rock cutting in column B:
$$
\begin{array}{ll|l}
\text{Column A (Method of drilling)} & & \text{Column B (Principle of rock cutting)} \\
\hline
P & \text{Diamond drilling} & 1.\ \text{Impact action} \\
Q & \text{Percussive drilling} & 2.\ \text{Thermal spalling} \\
R & \text{Rotary roller drilling} & 3.\ \text{Rotary abrasive} \\
S & \text{Jet piercing} & 4.\ \text{Cutting \& Ploughing} \\
\end{array}
$$