Mary and Charles have owned a beach cottage on the New Jersey shore for several years and have always used it as a family retreat. When they acquired the property, they had no intentions of renting it. Because family circumstances have changed, they are considering using the cottage for only one week a year and renting it for the remainder of the year. Their AGI approximates $100,000 per year, they are in the 30% tax bracket (combined Federal and state), and their total itemized deductions exceed the standard deduction amount. Interest and real estate taxes total $8,000 per year and are expected to continue at this level in the foreseeable future. If Mary and Charles rent the property, their incremental revenue and expenses are projected to be:

Why is the cournot equilibrium an​ equilibrium? a. there are​ short-run barriers to exit in a cournot​ duopoly, so both firms cannot alter their output levels. b. given the other​ firm's level of​ production, both firms are maximizing profits and cannot improve their situation by unilaterally altering their level of output. c. both firms operate at zero profit under a cournot​ equilibrium, so they would face negative profits if they change output. d. both firms operate at minimum​ long-run average cost under a cournot​ equilibrium, so changes to output would reduce​ long-run profits. even if they​ can't collude, why​ don't firms set their outputs at the joint​ profit-maximizing levels​ (i.e., the levels they would have chosen had they​ colluded)? a. given that other firm produces at the collusive​ level, a firm could increase their own profits by increasing output above the collusive level. b. the midpoint of the collusion curve​ (i.e., the collusive​ outcome) lies below the reaction​ curves, so both firms have an incentive to increase output under the cournot duopoly. c. both a and b are correct d. both a and b are incorrect