In $Fe-Fe_{3}C$ phase diagram, the eutectoid composition is $0.8$ weight $\%$ of carbon at $725^{\circ}C$. The maximum solubility of carbon in $\alpha$-ferrite phase is $0.025$ weight $\%$ of carbon. A steel sample, having no other alloying element except $0.5$ weight $\%$ of carbon, is slowly cooled from $1000^{\circ}C$ to room temperature. The fraction of pro-eutectoid $\alpha$-ferrite in the above steel sample at room temperature is

1. $0.387$
2. $0.864$
3. $0.475$
4. $0.775$