On 6/1, S publishes an ad in the local paper offering $100 to anyone who finds her dog and returns him to her. B goes out looking but is unable to find the dog. Meanwhile, C, who is initially unaware of the ad, finds the dog. C does not know who owns the dog until she happens to see S's ad in the paper, at which point she returns the dog to S. Which of the following statements describes the most likely disposition of the parties' rights?