Imagist: This problem has one obvious variation and a simple tesuji variation, but the really interesting thing about the problem is a hamete at .
This may seem stronger, but black plays the two stone edge squeeze and white's plan comes to naught.
a and b are still miai.
This is potential hamete, trying to set up the under the stones tesuji.
is correct; black must resist the temptation to play
at a.