a) White to move and mate in one.

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b) White to move and mate in two.

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c) White to move and mate in two.

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d) White to move and mate in two.

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Solutions:   a) B-c5 mate            b) N-e5ch, R-f7   folowed by  BxR mate            

c) BxNch, K-d8  followed by  Q-d7 mate           d) R-a7ch (other moves are possible), K-f8  then Q-f7 mate