How should Black play to gain the most points?
There are no prisoners, and the komi is 0.5.
(;LB[ea:A][ei:B]SZ[9]C[Black to move. Which is bigger, A or B?]AW[ag]AW[bg]AW[ch]AW[dh]AW[eh]AW[bf]AB[ae]AB[be]AB[cf]AB[df]AB[de]AB[dd]AB[cd]AB[bd]AW[cg]AB[dc]AB[db]AW[eb]AW[ec]AW[ed]AW[ee]AW[ef]AW[eg]AB[fh]AB[fg]AB[gg]AB[hg]AB[ig]AB[ie]AB[he]AB[ge]AB[gf]AW[ff]AW[gd]AW[hd]AW[id]AW[af]AW[fd]AB[hi]AW[dg]AP[goproblems]
(;B[ea]C[RIGHT Correct! Black = 18; White = 15.5. The final plays may go like this . . .]AW[fa][gb][di]AB[da][ei][fi]LB[fa:1][da:2][gb:3][ei:4][di:5][fi:6])
(;B[ei]C[CHOICE Sorry, White wins. Black = 16; White = 17.5. The final plays may go like this . . .]AW[da][ea][di]AB[ca][bb][fi]LB[da:1][ca:2][ea:3][bb:4][di:5][fi:6])
(;B[fa]C[NOTTHIS])
(;B[fb]C[NOTTHIS])
(;B[da]C[NOTTHIS])
(;B[ca]C[NOTTHIS])
(;B[cb]C[NOTTHIS])
(;B[fi]C[NOTTHIS])
(;B[di]C[NOTTHIS])
(;B[gi]C[NOTTHIS])
(;B[ci]C[NOTTHIS])
(;B[gh]C[NOTTHIS])
(;B[gb]C[NOTTHIS])
(;B[ga]C[NOTTHIS]))