9. An incumbent (I) can advertise (A) or not (N), and a potential entrant (P) can enter (E) or stay out (O). The payoffs for combined actions in matrix form are as follows: P E O A 1, -1 3. 0 N 2, 1 4, 0 a. Find all Nash Equilibria in the static game. b. Suppose P decides to enter or not, and then I decides to advertise or not. Find all Subgame Perfect Nash Equilibria. c. Suppose I decides to advertise or not first, and then P decides to enter or not. Find all Subgame Perfect Nash Equilibria