Compound. The simple sentence would be 'they were very busy'
Answer: B. rationality versus superstition
Explanation: The narrator is in disbelief of something supernatural like that happening because they are trying to remain rational.
Kapos are the guards who are in charge of each barrack and work station.
C is the right one. Unlike quotations or paraphrased ideas, information that's considered "common knowledge" doesn't need to be cited. "Common knowledge" is information that's considered widely known or easily verified.