Which of the Following Statements About Improving Readability Is True

Which of the following statements about improving readability is true?

A) Grammatically parallel headings and bullets reduce readability and should not be used.
B) The greater the complexity of a document, the fewer headings and subheadings it should have.
C) Long sentences are the best way to convey complex ideas or list a number of related points.
D) One-sentence paragraphs are easy to understand and should be used widely in business writing.
E) Bulleted lists should only be used when items are ranked; numbered lists are preferred.