(;AB[ra]AB[rb]AB[rc]AB[qd]AB[pd]AB[oc]AB[mc]AB[nc]AB[lc]AB[kc]AB[kb]AB[ka]AB[ma]AW[la]AW[lb]AW[mb]AW[nb]AW[ob]AW[pc]AW[qb]AW[qa]C[Black to kill]AP[goproblems]
(;B[na]
(;W[qc]
(;B[pa]C[CHOICERIGHT])
(;B[pb];W[pa])
(;B[oa];W[pa]))
(;W[oa]
(;B[pb];W[pa]
(;B[qc]C[CHOICERIGHT])
(;B[na];W[qc]))
(;B[qc];W[pb])))
(;B[pb];W[pa]
(;B[qc];W[na];B[pb]C[Fault. It's a Ko.])
(;B[na];W[qc])
(;B[oa];W[na];B[qc];W[pb]))
(;B[qc];W[pb])
(;B[pa];W[pb])
(;B[oa];W[na])
(;B[od];W[qc]
(;B[pa];W[pb])
(;B[pb];W[pa])
(;B[na];W[oa])))