Final answer:
The correct answer is d) They are used to cite sources within the text of a document, and in-text citations include the author's last name, and sometimes a page or paragraph number, whether the information is directly quoted, paraphrased, or summarized.
Step-by-step explanation:
The most accurate statement about in-text citations is d) They are used to cite sources within the text of a document. In-text citations are essential in MLA-style essays and serve to ethically credit the original authors for their work while also allowing readers to locate the more detailed Works Cited information.
They typically include the author's last name and often a page number or other locator such as a paragraph or line number. This is true whether the material is a direct quotation, a paraphrase, or a summary.
It's also important not to confuse direct quotations with paraphrases, as misrepresenting a quotation as a paraphrase can be considered plagiarism.
Remember that every in-text citation should have a matching entry on the Works Cited page and that citations are needed to support your argument, but should not overwhelm your own original ideas and analysis.