I'm pretty sure taking someones idea or words without giving the original source is plagiarism.
Answer:
C) Keep it, because it previews the way the rest of the passage will support the thesis about Hale’s authorship with evidence.
Explanation:
The writer should keep the underlined portion of the sentence because, as a thesis statement, it previews the line of reasoning of the passage. With the underlined text included, the writer makes it clear that the rest of the passage will provide strong evidence to support Hale’s authorship of the poem and discredit the idea that Sawyer inspired the poem.