Verifying Attack Manual 1(Quality Chess 2008)-Position 2

Verifying Attack Manual 1(Quality Chess 1st ed 2008)
I have been checking games usually but recently have been neglecting tactical work. Now I'm going through this book which has some exercises in ch9.

Here is the feature game and my notes to solution.

Aagaard,Jacob (2370) - Almasi,Istvan (2425)

French Tarrasch[C07]

Budapest FS09 GM Budapest (6), 1996

Position 1
White is lined up against the kingside with obvious attacking intensions. What do you recommend for white?

White to Play

21...g6