Scott, manufacturer of a carbonated beverage, entered into a contract with Otis, owner of a baseball park, whereby Otis rented to Scott a large signboard on top of the center field wall. The contract provided that Otis should letter the sign as Scott desired and would change the lettering from time to time within forty-eight hours after receipt of written request from Scott. As directed by Scott, the signboard originally stated in large letters that Scott would pay $1,000 to any ballplayer hitting a home run over the sign. In the first game of the season, Hume, the best hitter in the league, hit one home run over the sign. Scott immediately served written notice on Otis instructing Otis to replace the offer on the signboard with an offer to pay $500 to every pitcher who pitched a no-hit game in the park. A week after receipt of Scott’s letter, Otis had not changed the wording on the sign. On that day, Perry, a pitcher for a scheduled game, pitched a no-hit game while Todd, one of his teammates, hit a home run over Scott’s sign. Scott refuses to pay any of the three players. What are the rights of Scott, Hume, Perry, and Todd?