(;SZ[4]AB[ad]AW[bd]AW[cd]AB[dd]AB[ab]AB[bb]AB[cb]AB[db]AW[ba]AW[ca]AW[aa]AW[cc]C[You would wonder such a lot of correct answers but this problem represents 'What happens when the situation of the board is like this'. If you don't like this problem, just close it.]AP[goproblems]
(;B[ac]C[RIGHT])
(;B[bc]C[RIGHT])
(;B[da]C[RIGHT])
(;B[dc];W[ac]C[What should Black do if he doesn't pass?]
(;B[da];W[ba]
(;B[bc]
(;W[aa]
(;B[ad]C[RIGHT])
(;B[ca]
(;W[aa]
(;B[ad]C[RIGHT])
(;B[ba];W[aa]))
(;W[ba]
(;B[ad]C[RIGHT])
(;B[aa];W[ba]))))
(;W[ca]
(;B[ad]C[RIGHT])
(;B[aa]
(;W[ba]
(;B[ad]C[RIGHT])
(;B[ca];W[ba]))
(;W[ca]
(;B[ad]C[RIGHT])
(;B[ba];W[ca])))))
(;B[aa];W[bc]
(;B[ad]C[RIGHT])
(;B[ca];W[ba]))
(;B[ca];W[bc]
(;B[ad]C[RIGHT])
(;B[aa];W[ba])))
(;B[bc];W[da])))