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Two movie studios, A and B, must decide when to release their blockbuster movies. There are two options: November or December. In the November release date there are enough viewers to sell tickets valued at a total of $500 million. In the December release date, the total is $800 million. If only one of the studios opens during a given release date, then it takes the whole pie. If two studios open during the same weekend, then they share the pie (equally). Since studio A has a close relationship with various movie theater chains, it makes its choice ahead of its rival. Moreover, studio A can commit to its choice and the choice is observable by studio B. (a) Describe the game formally and determine its Nash equilibrium (or equilibria, if there is more than one). (b) Suppose that, before studio A makes its choice, studio B has the opportunity to write a contract with advertisers for the week before the release date. Suppose that the cost of advertising is the same in November and December; and that, if studio B wants to change the date after signing the initial contract, it must pay a penalty for breach of contract equal to $120 million. Determine the subgame perfect equilibrium of the new game