Sunk costs and decision-making Bob has plans to go to an opera and already has a $100 nonrefundable, nonexchangeable, and nontransferable ticket. Now Cho, whom Bob has wanted to date for a long time, asks him to a concert. Bob would prefer to go to the concert with Cho and forgo the opera, but he doesn't want to waste the $100 he spent on the opera ticket. From the perspective of an economist, if Bob decides to go to the opera, he has: Made an optimal choice Correctly ignored a sunk cost Incorrectly allowed a sunk cost to influence his decisio