(1) In this Regulation "allowable contribution" means a contribution or a deduction payable by an employee and deductible by an employer from emoluments of the employee and which is -

(a) by virtue of section 471 of the Act, allowable as a deduction from such emoluments for the purposes of assessment under Schedule E,

(b) an ordinary annual contribution, or any other contribution treated by the Revenue Commissioners, as respects the year in which it is paid, as an ordinary annual contribution paid in that year, allowable by virtue of section 774 or 776 of the Act, as a deduction from such emoluments for the purposes of assessment under Schedule E,

(c) by virtue of section 787C of the Act, to be deducted from or set off against the employee's relevant earnings (within the meaning of section 787B of the Act) for the year of assessment in which it is paid,