Under the FIA Act 1974, member of the FIA not below the rank of _____ shall be deemed to be an officer-in-charge of a Police Station for the purposes of any inquiry or investigation.

(A) Inspector
(B) Sub-Inspector
(C) Assistant Sub-Inspector
(D) Head Constable

Answer:
(B) Sub-Inspector

FIA Act, 1974 Para 5(2) says,

Subject to rules, if any, a member of the Agency not below the rank of a Sub-Inspector may, for the purposes of any inquiry or investigation under this Act, exercise any of the powers of an officer-in-charge of a Police Station in any area in which he is for the time being and, when so exercising such powers, shall be deemed to be an officer-in-charge of a Police Station discharging his functions as such within the limits of his station.