Below, draw a game tree that accurately represents the following strategic situation: Two states, A and B, are engaged in an arms race. State A moves first and has the option to sign an arms control treaty (S) or not (∼S). B observes A’s choice of whether or not to sign, and following either, may itself choose whether or not to sign (s) or (∼s). Following B’s decision to sign, the game ends if at least one side signed the treaty. If both signed, each receives 3 utility. If one state signs and the other does not, the non-signer gets 5 while the signer gets 0. If both sides choose not to sign the treaty, the game does not end. Instead, the arms race continues, and A begins by having the option to either expand their arsenal (E) or not (∼E). This move occurs in secret and is not observed by B. After A’s expansion decision, B may also choose whether or not to expand their own arsenal (e) or (∼e), and the game ends. During the arms race, if both states do not expand, each receives 4 utility. If both expand, each receives 2. If one expands while the other does not, the state that expands receives 6 utility and the other 1.