Which story line primarily concerns external conflict?

In “To Build a Fire,” a newcomer sets out alone on foot when the temperature is seventy-five degrees below zero.
In “Two Friends,” one man must decide between his own personal safety and the safety of his friend.
In “One Thousand Dollars,” a carefree young man has inherited a small sum with the condition that he reports how he spends it.
In “The Monkey’s Paw,” a couple is given the opportunity to ask for three wishes.