Beginner Exercise 288 / Solution

Solution  

Black fights a ko for life.

Failure  

Black can secure an eye at the bottom with , but then White will destroy the eye on top with and kill the whole black group. After that, black is reduced to one eye: a and b are miai. at c also kills, but is inferior, giving Black one more ko threat.

Failure  

is a weak defense. White can kill with , a or even b. In either case, black can't make a second eye at the bottom.