Which conclusion can be formed based on the information
in the excerpt?
The mushers were more concerned about their own
safety than the sick people in Nome.
The mushers' lungs were so used to cold Arctic air that it
no longer posed problems for them.
The mushers risked their own lives and their dogs' lives
to help the people of Nome.
The mushers' exposure to cold Arctic air caused them
problems with their eyesight.