Match the drugs in $\text{Group I}$ with their mechanism of action in $\text{Group II}$

$\begin{array}{|l|l|l|l|} \hline & \textbf{Group I} && \textbf{Group II} \\ \hline P. & \text{Paclitaxel} & 1. & \text{Inhibits protein translation} \\ \hline Q. & \text{Colchicine} & 2 .& \text{Inhibits microtubule depolymerization} \\ \hline R. & \text{Etoposide} & 3. & \text{Inhibits DNA replication} \\ \hline S. & \text{Methotrexate} & 4. & \text{Alkylates DNA} \\ \hline && 5. & \text{Inhibits dihydrofolate reductase} \\ \hline && 6. & \text{Inhibits microtubule polymerization} \\ \hline \end{array}$

1. $P-1, Q-6, R-3, S-4$
2. $P-2, Q-6, R-3, S-5$
3. $P-1, Q-3, R-6, S-5$
4. $P-2, Q-3, R-6, S-4$