Final answer:
The primary conflict in Jack London's "To Build a Fire" is a struggle of character vs. nature, as the man battles the extreme cold of the Yukon without proper preparation or understanding of his environment.
Step-by-step explanation:
The primary conflict in Jack London's "To Build a Fire" is character vs. nature. The protagonist, braving the extreme cold of the Yukon, underestimates the severity of his environment which highlights his conflict against the unforgiving natural elements. Without proper equipment and experience,
he struggles to keep warm and make his way to safety. His numerous attempts to protect himself from the cold, such as rubbing his cheekbones and nose to keep them from freezing, and his efforts to build a fire only to have it extinguished by falling snow, underscore the relentless struggle against nature.
Furthermore, the tension is heightened by the dog's instinctual knowledge of the dangers presented by the cold, in contrast to the man's lack of imagination and understanding.
The correct option for the primary conflict in the story is (d) character vs. nature.