$1\mathrm{.}82pts$

Samuel posts a notice on the community bulletin board offering a $$100$ reward to anyone who finds and returns his lost cat, Mr$.$ Whiskers. The notice specifies that the reward will only be paid if someone successfully brings back Mr$.$ Whiskers. Susan, a neighbor, finds Mr$.$ Whiskers and returns him to Samuel, expecting the $$100$ reward. What type of contract is at issue in this situation?

Bilateral contract

No contract

Express contract

Implied contract

Unilateral contract