Lasker's Originality

I am watching chess videos that are part of the Fritz Trainer DVD, Master Class, vol. 5: Emanuel Lasker (2015). Mihail Marin makes the argument that Emanuel Lasker was an original strategic player who sought to bring new ideas into familiar openings. In the fourth game of his World Championship match with Siegbert Tarrasch, Lasker brought his rook to the fifth rank, then transferred in to the fourth, where tactical complications ensued. Tarrasch made a few small errors, leading to this position.

Black to move

How should Black deal with the fork?