The correct answer is D. Paradox
The human soul is often something that is valued a lot, almost priceless according to popular beliefs. It is a paradox because it is paradoxical that something so valuable is carried by something so frugal as a human body.
ANSWER(S):
B. asserted
EXPLANATION(S):
A. murmured: too subtle
B. asserted: adequate
C. commented: too monotonous
D. snarled: too aggressive
The selfishness of humanity for sure, and I believe the harmony of life after death, I'm not 100 percent sure about that one.