Which statement is correct?

Select one:

a. In simultaneous-move games, Subgame Perfect equilibrium is different from Nash equilibrium b. If the game can be solved by backward induction, then Backward Induction equilibrium is the same as Subgame Perfect equilibrium

c. Let Player 1 move first and Player 2 move second without observing Player 1's earlier move. This is a sequential-move game.

d. In a sequential-move game, if the order in which players move is changed, then the concept of Subgame Perfect equilibrium cannot be applied