Sentence:  Meaningful policies include : ( a ) kinds of cars the state should own , ( b ) when cars should be <WSD>traded</WSD> , ( c ) the need and assignment of vehicles , ( d ) use of cars in lieu of mileage allowances , ( e ) employees taking cars home , and ( f ) need for liability insurance on state automobiles . 
Meaning of the word marked with <WSD> tags:  turn in as payment or part payment for a purchase