Long Moscow Variation

White is threatening a little something on h7. Now the sequence 23...Ne2++ 24.Kh2 Bg1+ 25.Kh1 Ng3+ ultimately yields Black ...
A)... a material advantage;
B)... a material disadvantage;
C)... neither nor (equality).
Extra question: Why does 23...Nf5+ 24.Kh2 Kg7 or 23...Nf3+ 24.Kh1 Kg7 fail?