(a)The Commissioner may, subject to such restrictions and conditions as may be prescribed, permit any registered dealer, who carries on wholly or partly the business of supplying goods in the course of execution of works contract entered into by him, to pay in lieu of tax payable by him under this Act a lump sum at such rate as may be prescribed and determined in the prescribed manner, by way of composition, and this option for composition will have to be submitted within [60 days] of commencement of execution of the works contract or contract.