A thief has seen a possible victim and is deciding whether to attack (A) or to pass (P). If he attacks, the victim must decide whether to defend (D) or surrender (R). If the thief does not attack, both players get a zero payoff. If the thief attacks and the victim surrenders, the thief gains an amount V>0 from the victim (so the victim gets -V); if the victim defends, the thief obtains only V/2 from the victim (the victim gets -V/2). When the victim defends, a violent dispute occurs, and both the thief and the victim suffer a cost C for the fight (-C added to their payoffs).

2.1 Find all Subgame Perfect Nash equilibria in pure strategies when C > V/2

2.2 Find all Subgame Perfect Nash equilibria in pure strategies when 0

my teachers answers were {A,S} for the first spne

and {A,D} for 2.2,

I am looking for explanations on how they got this answers