Final answer:
The man values the old-timer's advice as invaluable after realizing the danger he's in for not following it initially. If the man had initially heeded the old-timer's advice, he might not have been in the dangerous situation of having to build a second fire under emergency conditions.
Step-by-step explanation:
The man in the passage reflects on the advice given to him by the old-timer on Sulphur Creek.
Considering that he had to build the fire a second time to avoid severe consequences, such as losing toes to frostbite, it's clear he recognizes the value of the old-timer's advice.
Therefore, the best answer to the question "Since the man had successfully built the second fire, he feels the old Timer's advice was" is B) Invaluable.
If the man had initially heeded the old-timer's advice, he might not have been in the dangerous situation of having to build a second fire under emergency conditions.