(;AB[pc]AB[qc]AB[rc]AB[sb]AW[sc]AW[sd]AW[rd]AW[qd]AW[pd]AW[ob]AW[od]AW[oc]C[Can black live (unconditionally or by ko)? If not, please play at D (dead).]LB[qf:D]AP[goproblems]
(;B[qf]C[Black is dead.RIGHT])
(;B[ra];W[pa]
(;B[qa];W[qb])
(;B[qb];W[qa])
(;B[pb];W[qa]))
(;B[qb];W[ra])
(;B[qa];W[pb]
(;B[qb];W[ra])
(;B[ra];W[qb]))
(;B[pb];W[qa]
(;B[pa];W[rb])
(;B[ra];W[pa])
(;B[qb];W[pa])))