.
(a) In three ways. It is so OBVIOUS that does not require justifications.
(b) She can select any of the 3 trails up and any of the 3 trails down.
In all, there are 3*3 = 9 different ways.
(c) For any of the three trails up, she can choose any of the two remaining trails down.
In all, there are 3*(3-1) = 3*2 = 6 different choices.
Solved and thoroughly explained.
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From my post, learn two things:
1) How to make an analysis,
and
2) How to use appropriate English words correctly in Math problems.