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)