(d) Area under given curve represents emissive power and emissive power $\propto T^{4} \Rightarrow A \propto T^{4}$
$\Rightarrow \frac{A_{2}}{A_{1}} = \frac{T_{2}^{4}}{T_{1}^{4}} = \frac{(273 + 327)^{4}}{(273 + 27)^{4}} = \left( \frac{600}{300} \right)^{4} = \frac{16}{1}$