Match the chemical (Column I) with its use (Column II).
\begin{array}{|c|c|c|}
\hline \text{Column I} & \text{Column II} \\
\hline \text{P. Diethylpyrocarbonate} & 1. \text{Chelation of magnesium ion during DNA purification}\\
\hline \text{Q. Cesium chloride} & 2. \text{Prevention of RNA degradation in aqueous environment}\\
\hline \text{R. Ethidium bromide} & 3. \text{Separation of DNA by density gradient centrifugation}\\
\hline \text{S. Ethylenediaminetetraacetic acid} & 4. \text{Staining of RNA in agarose gel} \\
\hline
\end{array}
- $\text{P-4; Q-1; R-3; S-2}$
- $\text{P-4; Q-3; R-2; S-1}$
- $\text{P-2; Q-1; R-4; S-3}$
- $\text{P-2; Q-3; R-4; S-1}$