The correct statement about textual features is:
B. Titles divide material into manageable segments.
Here's a brief overview of the other options:
A. Headings are generally presented in a larger or bolder font than the rest of the text, not smaller.
C. Graphs, charts, and images are typically used to clarify and simplify ideas, not make them seem more complicated.
D. A table of contents and an index are more commonly found in longer documents, such as books, rather than very short documents.