(b)A deduction shall also be allowed under this sub-section in respect of the aggregate of expenditure (not being in the nature of capital expenditure), related to business, incurred on—(i)salary to an employee engaged in such scientific research; or(ii)purchase of materials used in such scientific research, where such expenditure is incurred within three years immediately preceding the commencement of business, to the extent certified by the prescribed authority as incurred on such research and such expenditure shall be deemed to have been incurred in the tax year in which the business is commenced.