Where any tax is—
(a) deducted under section 77 from employment income accrued to any person;
(b) deducted under section 78 from a payment to any contractor; or
(c) paid in advance of a notice of assessment under section 113 or otherwise,
the tax so deducted shall be set off against the tax charged under section 80(1) for the year of income in relation to which such income accrued.