I don't think any of the choices fully expresses what Wiesel is trying to convey.
The key word in the choices seems to be immediacy, but that word is totally inadequate to express what is going on. Excited immediacy is what I expect to hear from a commentator telling me what is happening during a sports event.
This passage has an immense sadness and pathos connected to it. It is sad to read of a child that knows it will die. It is sad to read of a man who thinks nothing of himself and tries to comfort those who share his fate with him. It is sad to think of a child who asks permission to cry. All of these things are details that we would never think of when reading fiction. They must be based on actual experience.
The reality of this passage is conveyed, perhaps too intellectually, by the word existential. I don't like the word much, but it is the only word that describes how anyone could record events like those in the passage. So that is the answer I would choose. It doesn't come within a mile of describing what's there.
But neither does anything else.
Answer: Existential