(;AW[mb][lc][nc][oc][rc][sc][md][pd][qd][re]AB[pb][rb][sb][pc]
(;B[qc]CR[qc]
(;W[qa]CR[qa]C[CHOICE]
(;B[ra]CR[ra]
;W[pa]CR[pa]
(;B[ob]CR[ob]
;W[oa]CR[oa]
(;B[na]CR[na]
;W[nb]CR[nb]
;B[qb]CR[qb]C[RIGHT
Note however that with better play, white could have made a ko.])
(;B[nb]CR[nb]
;W[na]CR[na]))
(;B[oa]CR[oa]
;W[ob]CR[ob]
;B[qb]CR[qb]
;W[pa]CR[pa]C[Only one real eye.])
(;B[qb]CR[qb]
;W[oa]CR[oa]))
(;B[pa]CR[pa]
;W[ra]CR[ra])
(;B[ob]CR[ob]
;W[ra]CR[ra]))
(;W[pa]CR[pa]C[CHOICE]
(;B[ob]CR[ob]
;W[ra]CR[ra]
(;B[qa]CR[qa]
;W[qb]CR[qb]C[RIGHT
Indeed, ko is the best you can do])
(;B[oa]CR[oa]
;W[qa]CR[qa])
(;B[qb]CR[qb]
;W[qa]CR[qa]
(;B[nb]CR[nb]
;W[na]CR[na])
(;B[na]CR[na]
;W[nb]CR[nb])))
(;B[qa]CR[qa]
;W[oa]CR[oa])
(;B[oa]CR[oa]
;W[qa]CR[qa]
;B[ra]CR[ra]
;W[ob]CR[ob]
;B[qb]CR[qb]
;W[pa]CR[pa])))
(;B[ra]CR[ra]
;W[qb]CR[qb]
;B[qc]CR[qc]
;W[pa]CR[pa]
(;B[qa]CR[qa]
;W[oa]CR[oa])
(;B[ob]CR[ob]
;W[oa]CR[oa]
(;B[qa]CR[qa]
;W[na]CR[na])
(;B[na]CR[na]
;W[nb]CR[nb])))
(;B[qb]CR[qb]
;W[ob]CR[ob]
(;B[pa]CR[pa]
;W[ra]CR[ra])
(;B[ra]CR[ra]
;W[pa]CR[pa]))
(;B[ob]CR[ob]
;W[qc]CR[qc]
(;B[qb]CR[qb]
;W[ra]CR[ra]
(;B[oa]CR[oa]
;W[qa]CR[qa])
(;B[qa]CR[qa]
;W[oa]CR[oa])
(;B[nb]CR[nb]
;W[na]CR[na]
(;B[oa]CR[oa]
;W[qa]CR[qa])
(;B[qa]CR[qa]
;W[oa]CR[oa])
(;B[ma]CR[ma]
;W[la]CR[la])))
(;B[nb]CR[nb]
;W[qb]CR[qb])
(;B[qa]CR[qa]
;W[qb]CR[qb]))
(;B[qa]CR[qa]
;W[qc]CR[qc]))