(;CA[gb2312]AB[bq][cq][ds][eq][fq][fr][fs]AW[ar][aq][bp][cp][dp][ep][fo][gp][gq]
[gr][gs][er]C[Black first to live.
]AP[MultiGo:4.4.4]SZ[19]AB[br]MULTIGOGM[1]

(;B[dr];W[bs];B[cs]C[Black must respond at 3.];W[dq];B[as]C[If black chooses 1, it turns into a ko, not the best solution.])
(;B[dq];W[bs];B[cs];W[dr]C[If black plays 1, white still plays B1, and black dies with only one eye.])
(;B[bs]C[Answer];W[dr];B[dq];W[cr]C[Black lives with seki.]))