Which abbreviation is not acceptable when typing a reference list?

In APA formatting, the use of abbreviations is specific and regulated to ensure clarity and consistency. "D" is indeed the correct answer because "pg." is not an acceptable abbreviation in an APA reference list. Instead of "pg.," APA style properly uses the abbreviation "p." for a single page and "pp." for multiple pages. This is important because using the correct abbreviation ensures that readers can easily understand the references without confusion.

On the other hand, "No." for number, "pp." for pages, and "Vol." for volume are correctly formatted and accepted abbreviations within APA style. Maintaining these standards is vital for academic integrity and professionalism in research writing.