Answer:
attached below is remaining part of the detailed solution
A) SPNE = ( M,Y )
B) PSNE = ( U,Y )
Step-by-step explanation:
A) write down every subgame-perfect Nash equilibrium of the game
attached below
The second player can observe the first player's choice before making his own choice and the first player will always play M knowing that the second player will observe him, also the second player will play Y
Therefor the SPNE of the game will be : ( M,Y )
B) If the game were played simultaneously the results will be different and this is because the second player doesn't have the information of what the first player played
Therefore the PSNE of the game will be : ( U,Y )