An ac source is connected to a capacitor C . Due to decrease in its...

Capacitive reactance is given by,

${X}_{C} = \dfrac{1}{\omegaC} ⇒ {X}_{C} ∝ \dfrac{1}{\omega}$

Clearly, as $\omega$ decreases the value of the ${X}_{C}$ will increase.

Now, as impedance of the circuit is decreasing and as we know, conduction current will be equal to the displacement current, hence displacement current will decrease.