77. ¹[(1) The Deputy Commissioner of Taxes may, at any time after expiry of the date specified in section 75, by a notice in writing, require – (a) any person, other than a company, to file a return of his total income as provided in that section if, in the opinion of the Deputy Commissioner of Taxes the total income of such person was, during the income year, of such amount as to render liable to tax; (b) any company to file a return of its total income, if it is not filed.] (2) The return under sub-section (1) shall be filed within such period, not being less than ²[twenty-one days], as may be specified in the notice or which such extended period as the Deputy Commissioner of Taxes may allow.