(;
GM[1]
SZ[19]
AW[dd][gd][dp][jp][nq][lc][le][me][mf]
AB[ck][pp][pn][pj][pd][jd][ke][kf][lf]
LB[mg:A][og:B][pg:C]
TR[mf]
C[Problem 118. Black to play.  

White has just played the marked stone in order to prevent Black from confining her to the top. How should Black respond; at A, B, or C ? ]
(;B[pg]
TE[2]
C[Correct Answer.  

Black should defend the right side with 1. ]
;W[mh]
C[White must escape with 2 ... ]
;B[kh];W[mj]
C[... and 4, but ... ]
;B[kj]
LB[kh:3]
C[... Black moves out into the center with 3 and 5, pinning the white group against his stones on the right. <= ]
)
(;B[og]
C[Failure.  

Black 1 here would be an overplay. <= ]
)
(;B[mg]
C[Failure.  

Black 1 aims to confine White to the top, but ... ]
;W[oe]
C[... she responds with 2 ... ]
(;B[pe];W[ng]
C[... and 4, leaving Black without a good follow-up. <= ]
)
(;B[og]
C[If Black 3 here, ... ]
;W[pe]
C[... White will play 4 and Black will be unable to put his thickness to good use. <= ]
))
)