I believe the answer is C
The definition of a parable is: a simple story used to illustrate a moral or spiritual lesson, as told by Jesus in the Gospels.
The definition of pathos is: a quality that evokes pity or sadness
In the excerpt above, when Wiesel says "Only God and God alone can and must remember everything," he is using parable to illustrate how great God is, by giving an example of something he can do that not one person on earth can.
Also, by saying "Without the ability to forget, man would live in a permanent, paralyzing fear of death," Wiesel is using pathos to stimulate a feeling of sadness, as thinking of how paralyzing fear of death cannot be very pleasant.