Concept:The idiom "keep the wolf away from the door" means to earn or have just enough money to satisfy basic needs and avoid extreme poverty or hunger.
Explanation:John's money was "barely enough" to keep the wolf from the door.
"Barely enough" means the amount was only just sufficient, with very little extra.
This sentence suggests that John could meet essential requirements such as food and shelter only by a very narrow margin.
The phrase does not mean John literally killed a wolf.
It also does not mean he spent money carelessly or lavishly.
Although the circumstances were difficult, the central idea is that the money was just sufficient for survival.
Therefore, the most appropriate interpretation is that John's money was just sufficient.
Answer:B. The money was just sufficient.