b
Total power consumed by electrical appliances in the building, \(P_{\text {total }}=2500\, \mathrm{W}\)

Watt \(=\) Volt \(\times\) ampere

\(\Rightarrow \quad 2500=\mathrm{V} \times \mathrm{I}\)

\(\Rightarrow \quad 2500=2201\)

\(\Rightarrow \quad I=\frac{2500}{220}=11.36 \approx 12\, \mathrm{A}\)

(Minimum capacity of main fuse)