C. Plagiarizing is not a step used to refine a thesis statement.
Explanation:
<u>Plagiarizing</u> refers to reproducing or using someone else's words, ideas or work as one's one or without attribution. In literature, this phenomena refers to the appropriation of ideas or passages from another author.
Therefore, unlike <em>asking</em>, <em>questioning </em>or <em>investigating</em>, C. plagiarizing is not a step used to refine a thesis statement.