Answer:
The correct option is letter B (IRONY).
Step-by-step explanation:
In "To Build a Fire" by Jack London, the author uses many instances of irony (situational irony). When the man, after having fallen into the water, finally succeeds in getting the fire on, the snow falls from the tree over him and the fire. As a result, the fire dies.
However, this instance of situational irony helps the plot move because he has to start a new fire.