Which of the following activities of a state should be accounted for in an Agency Fund? a. a lottery, wherein half the revenues is used for prizes and the other half is used for lottery operating expenses and to enhance revenues available for education purposes b. sales taxes collected on behalf of counties that elect to "piggy-back" their own sales tax onto the state sales tax, with the county portion to be remitted later to the counties c. contributions from the state and from local governments that will be invested and paid out to state and local government employees in the form of pension benefits d. highway taxes that will be used to finance improvements made to roads within the state