Answer: Attempt to make sense of the atrocities he experienced.
This is an autobiography, so it is a kind of recollection of his memories and trying to understand all of it.
However, he also wanted to tell about his first-hand experience with Holocaust (just like in his novel Night), and to warn the humanity about the consequences of keeping silent and ignoring the evil until it grows so strong that it starts threatening the whole world.
C. The church were the clergy, and they were just next to the nobility
