# A choke is used to

$(a)\;\text{reduce current in DC circuit } \\(b)\;\text{reduce current in AC circuit} \\(c)\;\text{Convert AC to DC } \\(d)\;\text{Convert DC to AC}$

In electronics a choke is an inductor used to block higher-frequency alternating current (AC) in an electrical circuit, while allowing lower frequency or DC current to pass.
Hence b is the correct answer.
edited Apr 2, 2014