An AC series circuit has XL<XC. Which one of the following correctly states the nature of the phase angle ϕ between the supply voltage and current in its phasor diagram?
a) ϕ is zero and the current is in phase with the voltage.
b) ϕ=−90∘ and the circuit behaves as a pure capacitor.
c) ϕ is negative and the current leads the voltage.
d) ϕ is positive and the current lags the voltage.