Notwithstanding anything contained in any other provision of this Ordinance, no question as to the source of any sum invested by any person in the purchase of bond issued or caused to be issued under Bangladesh Infrastructure Finance Fund during the period between the first day of July, 2010 and thirtieth day of June, 2012 (both days inclusive), shall be raised if the assessee pays, before the filing of return of income for the relevant income year, tax at the rate of ten per cent on such sum invested.]