Harry lost his new pet dog, a black-and-white Shetland sheepdog. He put up notices around his estate stating that he would give a reward of $200 to anyone who finds and returns his pet to him. A few years passed by with no results. Harry then just gave up hope that he would find his pet again. After 7 years, May brings a haggard looking black-and-white Shetland sheepdog to Harry and claims the reward.

Applying and citing the relevant principles of contract law, explain in your own words whether Harry was obliged to pay the reward