Because E claims that the first bolded portion is evidence. It is not evidence.

"The company is acting unwisely" is a conclusion/position supported by the evidence of increasing inventory. The overall argument is in disagreement with this position.

The first boldface text depicts the position that would be later on opposed in the passage. << the company is acting unwisely >> sounds like position taken on by the critics.
Second boldface portion says - <<However, the critics’ views are erroneous. Although >> The statement sounds like a position which is later on defended by providing further evidence. Safe to say, it sounds more of a conclusion, peruse the answer choices and 'C' matches closely with our predictions.

A. The first states the position that the argument opposes; the second offers evidence to discredit the support of the position being opposed.
second portion is not offering evidence, but is more of a position
B. The first states the position that the argument opposes; the second is evidence that was used to support the opposed position.
again, the word evidence is what we are not looking for, incorrect
C. The first states the position that the argument opposes; the second states the argument’s conclusion.
this sounds about right, keep it for later, go through other options
D. The first is evidence that was used to support a position that the argument opposes; the second provides data to weaken that evidence.
data to weaken the evidence sounds more providing inputs, but the boldface part is just making assertions, not providing any evidences
E. The first is evidence that was used to support a position that the argument opposes; the second states the argument’s conclusion.
It states that first part is an evidence, which is not correct; since it's an assertion by the critics, who say that company is acting unwisely. no evidence present there.