assessee

means a person by whom any tax or any other sum of money is payable under this Act, and includes—

 (a) every person in respect of whom any proceeding under this Act has been taken for the assessment of his income or assessment of fringe benefits or of the income of any other person in respect of which he is assessable, or of the loss sustained by him or by such other person, or of the amount of refund due to him or to such other person;

 (b) every person who is deemed to be an assessee under any provision of this Act;

 (c) every person who is deemed to be an assessee in default under any provision of this Act;