Does it check?
The move must attack the White King now.
These beginner mini-board positions practise attention, comparison and problem-solving. Check the king, compare candidate moves and try again when your first answer is wrong. Each correct choice is a real mate, the King has no safe square and cannot capture the checking piece safely. Black points up; White pieces are rotated. Edges of the diagram are board edges. Review moves on Pieces or the moves PDF first.
A wrong answer is feedback, not failure. Pause, review the board and try a different plan.
The move must attack the White King now.
Look at every adjacent square, including the board edge.
If the King takes the checking piece, that square must still be protected.
Start anywhere. A check mark only shows puzzles solved on this device.