QA: Subgame perfect Nash equilibrium in Three Player Extensive Form

Solving for subgame perfect nash equilibrium in a 3 player extensive form game.

[hnt]

Hi. At 6:30, when 1 selects A, shouldnt player 3 be unable to select any choices, rather only player 2 can select F? Thank you so much.

[ItsOnlyShift]

How do I do a 2 player game with 3 options