The purpose of the use of elongated hyphens in this excerpt is C. To interrupt the pattern of speaking in the normal flow of ideas.
Elongated hyphens are used to emphasize something, add extra information and even as a substitute for commas in some cases.
The other options are not correct because they don't cover the main function of the elongated hyphens which is to disrupt a sentence with extra information added to it.
C. To interrupt the pattern of speaking in the normal flow of ideas
The "elongated hyphens" are actually called “dashes.” Dashes should not be confused with hyphens (even though it takes two hyphens on a keyboard to make a dash). That said, dashes separate groups of words, not parts of words as does a hyphen. Words that interrupt the flow of a sentence are called “parenthetical,” and commas or parentheses are typically used to indicate/separate these words. However, in the instance where an author wishes for more emphasis and to highlight the parenthetical information, dashes are used, and when commas, dashes, or parentheses are used to interrupt the flow, the flow is interrupted in a grammatically correct manner.
