A choke is preferred in a capacitor to decrease the AC in a circuit because the capacitor:

Explanation

Choke coil is a coil with large inductance and small resistance. It is used in an ac circuit in order to reduce or control the current in the circuit. Let us consider a circuit which includes a voltage source which supplies a voltage of V=V0sinωt, a resistor of resistance R and a component Y which can be a choke coil or a resistance. First, let Y be a choke coil. As discussed before, choke is nothing but an inductor, so, the resulting circuit will be an LR circuit with impedanceZ=√R^2 +w^2 L^2. (see picture)Now, consider the case where Y is a resistor. This much reduction factor will not be obtained in the present case if you compare it with a choke coil.result, less power is consumed.Therefore, to reduce current in an ac circuit, a choke coil is preferred over a resistance because the choke coil consumes much less power..