A: diagram
1.rQxg6[bRc2; wrRg6] Kd4
2.rRd6 Kxc5[wSd4; brSc5]
3.Sb3+ rSb7+
4.rRd7+ Rc7#
B: bRg6-->f5
1.Se6 Kxe6[wSe5; brSe6]
2.rQxf5[bRc2; wrRf5] Rc6
3.Sc7+ rSg7+
4.rRg5+ Rg6#
C: bKe5-->c6
1.rQb3 Rd6
2.Se6 Rxd5[wSd6; brSc6]
3.Sd4+ rSa5+
4.rQxd5[bRb3; wrRd5]+ Rb5#
D=C: wrQc2-->f8
1.rQb8 Kxc5[wSc6; brSc5]
2.Se5 Rd6
3.Sd7+ rSa6+
4. rQxd6[bRb8; wrRd6]+ Rb6#