Answer:
C. Single-spaced.
Step-by-step explanation:
APA Style recommends using a single line spacing for the entire essay, including the title page, abstract, main text, references, and any other sections. This means that there should be no additional space between lines of text, except for double spacing between paragraphs.
Using single spacing helps to maximize the use of space on the page and ensure that the essay is presented in a clear and concise manner. It also makes the essay easier to read and follow.