Answer Notation:
1) KNa5; Pc5
2) BNb7+; Kb8
3) KNa6#
Answer Explained:
White KingKnight moves to a5. Black Pawn moves to c5 (only legal move black can make). White BishopKnight moves to b7, check. Black King escapes check by moving to b8 (only option). White KingKnight moves to a6, checkmate.