In need of money, the owner of a ring prepared an email one evening proposing to sell the ring to a friend for $500, but only if he responded within 24 hours. Unable to bring herself to send the email, the owner, who normally was a teetotaler, began drinking. When she was thoroughly intoxicated, she sent the email without realizing it. After the owner sobered up the following afternoon, she called her friend and said that she had never meant to send the email, but her friend informed her that he had already responded by email, agreeing to the transaction. Does a valid contract exist

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