aLegendWai (9k? KGS): Correct me if wrong.
Since you make such an assumption, it is already the best both parties can do in this endgame play. White(W) is protected by the circled white stone. B cannot do anything. W gets sente; B gets gote.
But as a whole board view, Black(B) might consider tenuki (play elsewhere) instead of since this endgame value is small. If B can find a bigger endgame value elsewhere, it is worthwhile for B to tenuki (play elsewhere) in order to get sente.
PS: Bill, I moved your question to the discussion section).
aLegendWai (9k? KGS): Alternatively, a throw-in play is possible and trickier. However if both parties answer correctly, the situation will be just the same as the "normal response" - with the same point difference, W getting sente; B getting gote. However any party can tenuki in the middle and is ahead of another to get sente.
aLegendWai (9k? KGS):