题目如下：
In contrast to most animals, humans are true killers; our
history is a record of destructiveness and cruelty. Do we
possess some uniquely human capacity for destruction, or
does human hyper- aggression have the same origin as
benign animal aggression?
In support of the latter assumption, it can be argued that
when an animal is deprived of space, it becomes vicious and
destructive. Thus, human hyperaggression is perhaps a
result not of our increased potential for aggression, but
rather of our being exposed more frequently. This
argument forces us to analyze the human condition in
history. We can infer that modern humans have lived
primarily in a “zoo” rather than in the “wild.” In fact, most
data about human nature closely parallel observations of
monkeys in crowded zoo conditions. Yet, even when not in
congested situations, humans often act destructively and
cruelly.

The two sentences in boldface play which of the following
roles?
A.The first proposes a hypothesis; the second refutes the
hypothesis.
B.The first proposes a hypothesis; the second provides
supporting evidence.
C.The first presents an argument; the second points out a
contradiction to that argument.
D.The first introduces a viewpoint; the second expands on
this viewpoint.
E.The first formulates a theory; the second makes an
adjustment to this theory.
答案是C，这个我可以理解。但是C好像和A差不多。请问是怎样排除掉A的？