The text feature, if added, that would best aid the reader's understanding of this passage is a heading that indicates the text's purpose.
Explanation:
The objective of using headings in writing is to give a simplified idea of the context to the reader without reading the complete information, this all shows if the information that follows it is important or necessary for the reader then for TopGuide Financial clients it would be practical to specify the main point of making them aware of this rules.
The definition of Ethos is an appeal to ethics, and it is a means of convincing someone of the character or credibility of the persuader. So your answer should be C.