Beginner Exercise 86 / Solution

Solution  

is the correct way to attack.

Solution  

and is the best play for both players, with White taking the ko first. Remember the sequence, this shape often occurs in practice.

Refer to Tripod Group with Extra Leg for more details.

Weaker defense  

here leads to another ko, but Black takes first. (try to get first capture in a ko).

Unconditional Life  

achieves nothing.