The specific heat capacity is defined as the thermal energy required to raise the temperature of a specific mass of a material a specific amount. The one with the highest specific heat capacity would have the smallest rise in temperature.
Since:
[tex]\begin{gathered} ci=Specific_{\text{ }}heat_{\text{ }}of_{\text{ }}iron=0.1 \\ ca=Specific_{\text{ }}heat_{\text{ }}of_{\text{ }}aluminum=0.2 \\ ca>ci \end{gathered}[/tex]We can conclude that the answer is:
a. Iron will reach 20° above room temperature first because it has a lower specific heat.