Answer:
Subject heading
Explanation:
Options you were given are the following:
- Title of the article;
- Volume and page number;
- Author's name and subject heading;
- Subject heading.
Out of the listed, the subject heading is the least likely to help you in locating an article you've already found in the Readers' Guide. Subject headings, which include a word/phrase or a group of words/phrases that most precisely represent what an article is about, are there to help you discover articles in the first place. Since you've already found the article, the subject heading is no longer of use, and other provided information (the title of the article, author's name, and volume and page numbers) should help you locate it.
