(d) Here, $\gamma = 1.5,\ V_{2} = \frac{1}{4}V_{1};\ \frac{p_{2}}{p_{1}} = ?$
As compression is sudden/adiabatic,
$\therefore\ \ p_{2}V_{2}^{\gamma} = p_{1}V_{1}^{\gamma}$
$\frac{p_{2}}{p_{1}} = \left( \frac{V_{1}}{V_{2}} \right)^{\gamma} = (4)^{1.5} = 8$