The State of Rio Grande entered into a contract with Roads, Inc., for construction of a fourlane turnpike. Prior to commencement of construction, the legislature, in order to provide funds for parks, repealed the statute authorizing the turnpike and cancelled the agreement with Roads, Inc. Roads, Inc., sued the state to enforce its original agreement. In ruling on this case, a court should hold that the state statute cancelling the agreement is
valid, because constitutionally the sovereign is not liable except with its own consent.  valid, because the legislature is vested with constitutional authority to repeal laws it has enacted.  invalid, because a state is equitably estopped to disclaim a valid bid once accepted by it.  invalid, because of the constitutional prohibition against impairment of contracts.