For a series $L-C-R$ circuit at resonance, the statement which is not true ?

In series $L-C-R$ circuit, $$ \begin{aligned} X_{L} &=X_{C} \\ \therefore \quad & Z=\sqrt{R^{2}+\left(X_{L}-X_{C}\right)^{2}} \end{aligned} $$ $$ \begin{aligned} &=\sqrt{R^{2}+0^{2}} \\ Z &=R \\ \therefore \text { Power factor } &=\cos \phi \\ &=\frac{R}{Z}=\frac{R}{R}=1 \end{aligned} $$ Hence, power factor is not zero. Therefore option (d) is not correct. In $L-C-R$ series resonance circuit, peak energy stored by a capacitor is equal to peak energy stored by an inductor. Average power, $P_{\mathrm{avg}}=V_{\mathrm{rms}} \times I_{\mathrm{rms}} \times \cos 0^{\circ}$ $$ \begin{aligned} &=V_{\text {rms }} \times I_{\text {rms }} \\ &=\text { apparent power } \end{aligned} $$ $L-C-R$ series resonance circuit is purely resistive because $X_{L}=X_{C}$, hence no wattless current exists in this circuit therefore wattless current is zero.