Daisy, the McCormi's family dog went missing one night. Upset about dog's disappearance and in desperate search for the beloved pet, the family posted several posters around the township announcing $500 reward for anyone who finds the missing dog.

John, who has not seen or heard aboutthe notices, found daisy while walking in the park and used the name tag information to identify the owners who happily recovered the pet.

What kind of contract did the reward offer seek to form-bilateral or unilateral?

Looking at these facts strictly as a matter of contract law, are the McCormics obligated to pay John the reward?