(1) Every such person required to file a return under section 166, 172, 175, 191, 193 or 212 shall pay the tax payable on or before the date of filing of the return.

(2) The tax payable shall be computed under the rule A — B, where—

A.        = tax payable by the taxpayer on the basis of the return or under the provisions of sub-section (5) of section 163, whichever is higher;

B.        = Tax paid at source or advance tax as per the provisions of Part VII.

(3) The amount paid under sub-section (1) shall be deemed to have been paid as tax payable by the taxpayer after assessment of regular tax.

(4) If any person, without reasonable cause, fails to pay the tax payable under sub-section (1); he shall be deemed to be a defaulting taxpayer.