C. Time
When the speaker is saying “miles to go before I sleep”, sleep can refer to death. By saying that they have miles to go before death means that they still have time left to live.
The reason the author may have chosen short sentences is to show Elie’s racing thoughts of depression, anxiety, and struggle with his pessimistic thoughts about possibly being chosen for the next (i think it’s called selection) selection to the ovens.
I hope this helps I tried to remember when I read this
