tds on hiring charges of bus

under which section the tds on hiring charges of buses should be deducted- whether under sec 194c or 194i. what interpretation i am deriving is sec 194i asks for decuction of tds on plant & machinery and income tax act has recognised 4 broad categories of assets:- land, plant & machinery, furniture & fixtures and buildings.so buses fall under plant & machinery category & consequently tds should be deducted under 194I not 194C