Kasparov has played Nd5 giving us the following position:-
Kasparov has chosen the sharpest line where he will potentially win the "exchange"- i.e. rook for a minor piece- knight or bishop. In this case we will be re-gaining Kasparov's knight. We will also have compensation for the exchange in the form of 2 pawns.
Of the move Nd5, British GM James Plaskett (2513), and former British Champion has written:-
11 Nd5 is sharpest, but I would be ready to take the black pieces after 11...Qxe4 12 Nc7+ Kd7 13 Nxa8 Qxc4.
Conclusions
The World has entered into a forcing variation now. Qxe4 is best.