While documenting, when is a block quotation used in prose?

The correct option is: If a quotation runs in more than five lines.

To understand when to use a block quotation in prose documenting, we can examine the formatting rules step-by-step:
1. Inline vs. Block Quotations: In professional and academic writing, shorter quotes are typically embedded directly within the normal flow of the prose using double quotation marks. However, very long quotes can disrupt the layout and readability of the text.
2. Formatting Block Quotations: When a quotation exceeds a certain length, it is presented as a "block quotation." A block quotation starts on a new line, is indented from the left margin to stand out visually, and does not require quotation marks around it.
3. Determining the Threshold: Depending on the specific style guide or documentation standard in use, a distinct threshold is established to trigger this formatting change. Under the standard referenced here, if a direct quotation runs in more than five lines of prose, it must be separated from the main text and formatted as a block quotation to maintain clean presentation and clear distinction between the source text and the author's own writing.