The line that draws power supply to your house from street has (a) zero average current. (b) 220 V average voltage. (c) voltage and current out of phase by 90°. (d) voltage and current possibly differing in phase φ such that |φ| < π/2.
Correct option is D) As the line has some resistance (R=0). Also, line that draws power supply has some inductance and capacitance, hence voltage and current differ in phase ϕ such that ∣ϕ∣<2π.
