Part a: which pair of events describes a significant cause and effect that occurs in the story

Clarification:

I found the complete instructions for the exercise online:

Which pair of events describes a significant cause and effect that occurs in the story?

Select one:

Cause: The men become aware that they are following their own footsteps. Effect: They lose faith in Ollendorff as a guide.

Cause: The men realize they might be wandering down a sagebrush path instead of a road. Effect: The horses wander away from the group.

Cause: The men get distracted while trying to light the fire with a pistol. Effect: The men are forced to change the way they navigate.

Cause: The men lose sight of the wagon tracks as the snow continues to fall. Effect: They decide to camp and make a fire.

Cause: The men become aware that they are following their own footsteps. Effect: They lose faith in Ollendorff as a guide.

Explanation:

To complete this exercise, you have to read the passage "Lost in the Snow" from Roughing it by Mark Twain and then select the correct option.

This story is about these men that were mounting in the snow and they couldn't perceive the road. They follow Ollendorff but after a while they realize they were following their own footsteps: "We certainly had been following our own tracks. Ollendorff and his 'mental compass' were in discrace from that moment."