I made up this new problem from the end of another one posted a few days ago.
(;GM[1]FF[4]CA[UTF-8]AP[CGoban:2]ST[2]
RU[Japanese]SZ[19]KM[6.50]
PW[Blanc]PB[Noir]AW[ba][cb][db][hb][ec][fc][gc][hc][dd][hd][he]AB[eb][fb][gb][bc][cc][dc][cd][ed][fd][gd][ce][cg]C[Best moves for black.]
(;B[ea]CR[ea]
;W[bb]CR[bb]
(;B[da]CR[da]
(;W[ab]CR[ab]C[CHOICE]
;B[ga]CR[ga]
;W[ha]CR[ha]
;B[ac]CR[ac]C[RIGHT Seki. This is the best sequence for both black and white.])
(;W[ga]CR[ga]C[CHOICE This move is a mistake for white ...]
;B[ab]CR[ab]
;W[ha]CR[ha]
;B[ac]CR[ac]
;W[fa]CR[fa]
;B[aa]CR[aa]
;W[ca]CR[ca]
;B[eb]TR[eb][fb][gb]C[RIGHT White ate the 3 marked stones, but black will end up with more points than the other variation where white doesn't do the mistake, so it is not good for white.]))
(;B[ab]CR[ab]
;W[da]CR[da]C[Black lose the capture race. This is not the best that black can do.]))
(;B[da]CR[da]
;W[ca]CR[ca]
(;B[bb]CR[bb]
;W[ea]CR[ea]C[This is not the best that black can do.])
(;B[ea]CR[ea]
;W[ga]CR[ga]C[This is not the best that black can do.]))
(;B[bb]CR[bb]
;W[ea]CR[ea]TR[eb][fb][gb]C[The marked stones are dead. This is not the best that black can do.])
(;B[fa]CR[fa]
;W[bb]CR[bb]
(;B[ab]CR[ab]
;W[da]CR[da]TR[fa][eb][fb][gb]C[The marked stones are dead. This is not the best that black can do.])
(;B[da]CR[da]
;W[ab]CR[ab]TR[da][fa][eb][fb][gb]C[The marked stones are dead. This is not the best that black can do.]))
(;B[ga]CR[ga]
;W[bb]CR[bb]
(;B[ea]CR[ea]
;W[da]CR[da]TR[ea][ga][eb][fb][gb]C[The marked stones are dead. This is not the best that black can do.])
(;B[da]CR[da]
;W[ea]CR[ea]TR[da][ga][eb][fb][gb]C[The marked stones are dead. This is not the best that black can do.])
(;B[ab]CR[ab]
;W[ha]CR[ha]TR[ga][eb][fb][gb]C[The marked stones are dead. This is not the best that black can do.])))