Alex Weldon: Here's my low double-digit / high single-digit kyu guess. I would play the sequence shown here ( is b), because the Black stone in the middle of the right side prevents White from getting a good extension from her two-stone wall, while black makes territory along the upper side and reduces the threat of a corner invasion. White is heavy now.
Of course, I'm probably wrong.
Warder05: It probably bears mentioning that this sequence is quite useful for high-handicap games since it depends on the presence of a stone at both star points (which in high handicap games is a given). Also, the follow-up moves on the part of black help to build box-shapes elswhere on the board.
unkx80: Your answer is perfect. =)
unkx80: Firstly, note that d is off topic as the center of attraction is now how to deal with the marked White stone.
If Black chooses 1 (a in the problem) then White 2 and 4 easily makes a base inside the san ren sei framework, which goes against the san ren sei principle of attacking the invading stones. Also, after White 4, the position of the marked Black stone is odd.
If Black chooses 1 (c in the problem) then White will gladly exchange the marked stone for the territory in the corner in this commonly used fuseki. Now the marked Black stone makes the entire shape overconcentrated, the shape would look much better if the stone at 1 is placed at e instead.
On to Fuseki Exercise 10.