In the single-period Principal-Agent Model with an opportunistic agent, the principal must always offer the agent a financial incentive contract because A) a fixed salary contract provides no incentive for the agent to provide effort after agreeing to the contract. B) a fixed salary contract is more expensive to the principal than a financial incentive contract. C) a fixed salary contract requires the principal to pay the agent a risk premium D) a fixed salary contract is more complicated than a financial incentive contract.