Answer: The answer is a book chapter.
Explanation: Just to elaborate a little bit on the answer, it can be added that when referencing a chapter in a book, the name of the author of the said chapter goes first, followed by the year in which the source was published. The title of the chapter, in quotation marks, follows. Finally, the entry must reflect the name of the editor of the book, as well as the title of the book—in italics—followed by the page numbers and the city and name of the publishing company.
