SOLUTION

Domestic electric wiring is basically done in parallel connection so that if one appliance stops working due to Some defect, all other appliances keep working normally. In the parallel circuit if R₁, R_2, and R3 are the resistances of different household electrical appliances and I current enters the circuit then the current passing through three resistances will be I₁, I_2, and I₃ so that total current I = I₁ +I₂ +I₃. Every appliance can draw the required amount of current. So, if one of the appliances gets fused or damaged, other circuits will work.

But in option (a) if suppose resistances of different appliances are connected in series, the same current will flow through all appliances. Thus if one of the appliances does not work circuit appliances could not draw current and will cause inconvenience. Hence series connection can not be used in domestic electrical wiring.

Option (c) and (d) i.e combination of series and parallel connections are also not suitable because current I will be distributed into I₁, and I₂ along with I (across R) which is in series. As explained above, if the first appliance would stop work or get damaged, then the entire circuit would break and no current will further flow.