Given below are two statements:
Statement I : When the frequency of an AC source in a series LCR circuit increases, the current in the circuit first increases, attains a maximum value and then decreases.
Statement II : In a series LCR circuit, the value of power factor at resonance is one.
In the light of statements, choose the most appropriate answer from the options given below.

For Statement I:

The current amplitude in a series $$LCR$$ circuit is given by: $$I = \frac{V}{\sqrt{R^2 + \left(\omega L - \frac{1}{\omega C}\right)^2}}$$

As frequency increases from zero towards the resonant frequency ($$\omega_0 = \frac{1}{\sqrt{LC}}$$), the net impedance decreases, causing the current to increase to its maximum value ($$I_{\text{max}} = \frac{V}{R}$$).

As frequency increases past resonance, the inductive reactance increases, causing the total impedance to grow and the current to decrease. Therefore, Statement I is true.

For Statement II:

The power factor is given by $$\cos\phi = \frac{R}{Z}$$.

At resonance, the inductive reactance equals the capacitive reactance ($$\omega L = \frac{1}{\omega C}$$), which makes the total impedance equal to the resistance ($$Z = R$$). This yields a power factor of:  $$\cos\phi = \frac{R}{R} = 1$$

Therefore, Statement II is true.