10. Playing it safe: Consider the following dynamic game: Player 1 can choose to play it safe (denote this choice by S), in which case both he and player 2 get a payoff of 3 each, or he can risk playing a game with player 2 (denote this choice by R). If he chooses R, then they play the following simultaneous move game: Player 2 A B C 8,0 0,2 player 1 D 6,6 2,2 (a) Draw a game tree that represents this game. How many proper sub- games does it have?