4. Consider following sequential games. For each game, find all subgame perfect Nash equilibria (Show the steps used to derive SPNE by highlighting the branches with the optimal actions) If there are more than one SPNE, then draw a new tree for each additional SPNE and highlight the tree branches with optimal payoff. a. Player 1 10 40 E Player 1 15 C D 11 b. Khrushchev Do not place missiles Place missiles JFK Air strike Do nothing Blockade Khrushchev Khrushchev NU Acquiesce Escalate Acquiesce EscalateC. Player 1 A C B Player 2 Player 3 Player 4 D E F G H Player 1 Player 1 o- W - -NAO WN - D K L M OO WM -WN- NW- N