(c)A company approved under clause (iia) of sub-section (1) of section 35 shall maintain separate books of account in respect of the sums received by it for scientific research, reflect therein the amount used for carrying on research, get such books of account audited by an accountant, and furnish the report of such audit duly signed and verified by such accountant to the Commissioner of Income-tax having jurisdiction over the case, by the due date of furnishing the return of income under sub-section (1) of section 139.