Given that, $E_k=\{(a, b) \in S: a b=k\}$ for $k \geq 1$ and $p_k=P\left(E_k\right)$
Now, $E_1=\{(1,1)\} \quad \Rightarrow \quad p_1=P\left(E_1\right)$
$$
\begin{aligned}
& \Rightarrow \quad p_1=\frac{1}{36} \\
& E_2=\{(1,2),(2,1)\} \Rightarrow p_2=P\left(E_2\right) \\
& \Rightarrow \quad p_2=\frac{2}{36} \\
& E_4=\{(1,4),(4,1),(2,2)\} \Rightarrow p_4=P\left(E_4\right) \\
& \Rightarrow \quad p_4=\frac{3}{36} \\
& E_6=\{(1,6),(6,1),(2,3),(3,2)\} \\
& \Rightarrow \quad p_6=P\left(E_6\right) \Rightarrow p_6=\frac{4}{36} \\
& \text { and } E_{30}=\{(5,6),(6,5)\} \Rightarrow p_{30}=P\left(E_{30}\right) \\
& \Rightarrow \quad p_{30}=\frac{2}{36}
\end{aligned}
$$
$\therefore$ From the above results, we get
$$
p_1 < p_{30} < p_4 < p_6
$$
Hence, option (1) is correct.