Which sentence uses punctuation correctly?

AYou are going to fall off the cliff unless you move back.
BI wore my special hiking boots, so that I would not lose my grip.
CI won't leave you alone, until you retreat from the edge.

Verified Answer :

AYou are going to fall off the cliff unless you move back. (Not it aswell)
b. I wore my special hiking boots, so that I would not lose my grip. (Correct!)
c. I won't leave you alone, until you retreat from the edge. (No comma needed between alone and until)
growl

I wore my special hiking boots, so that I would not lose my grip