Both the demand curve and the supply curve are straight lines. If the price is $4 but only 6 units are bought and sold, producer surplus will be

When used-car dealers signal the quality of a used car with a warranty, a. buyers believe the signal because the cost of a false signal is high b. it is not rational to believe the signal because some used-car dealers are crooked c. the demand for lemons is eliminated d. the price of a lemon rises above the price of a good used car because warranty costs on lemons are greater than warranty costs on good used cars