A copper coin was electroplated with $\mathrm{Zn}$ and then heated at high temperature until there is a change in colour. What will be the resulting colour?

A copper coin was electroplated with zinc (Zn) and then heated at high temperature until there is a change in colour. The resulting colour will be golden. The golden colour is due to the zinc migrating through the copper to form the alpha-form of brass alloy (percentage of $\mathrm{Cu}>65 \%$ and that of $\mathrm{Zn} < $ $35 \%)$ $$ \mathrm{Zn}+\mathrm{Cu} \stackrel{\Delta}{\longrightarrow} \text { Brass } $$ Thus, the option (d) is correct answer.