The tax under this Act shall be payable by the assessee directly in the following cases, namely:—

(a) in any case where tax has not been deducted or collected as required by, and in accordance with, the provisions of this Part;

(b) in any case where the amount deducted or collected is found, after regular assessment, to be less than the tax due from the assessee, to the extent of deficiency;

(c) in the case of income in respect of which no provision has been made for deduction or collection of tax under this Part.