(b)  "alternate minimum tax" means the amount of tax computed on adjusted total income,—

  (i)  in case of an assessee being a unit referred to in sub-section (4) of section 115JC, at a rate of nine per cent;

 (ii)  in any other case, at a rate of eighteen and one-half per cent;

(ba) "convertible foreign exchange" means a foreign exchange which is for the time being treated by the Reserve Bank of India as convertible foreign exchange for the purpose of the Foreign Exchange Management Act, 1999 (42 of 1999) and the rules made thereunder;

(bb) "International Financial Services Centre" shall have the meaning assigned to it in clause (q) of section 2 of the Special Economic Zones Act, 2005 (28 of 2005);

(c)  [***]

(d) "regular income-tax" means the income-tax payable for a previous year by a person on his total income in accordance with the provisions of this Act other than the provisions of this Chapter.

(e)  "unit" means a unit established in an International Financial Services Centre.