What is an example of a reverse member expansion?

• A. TreeDescendantsR
• B. RTreeDescendants
• C. TreeDescendantsReverse
• D. ReverseTreeDescendants

Answer: (A)

Reverse member expansion is indicated by using the reverse form of a member-expansion function, typically shown with a trailing R. This naming convention signals that the expansion will proceed in the reverse way compared to the standard descendants expansion. TreeDescendantsR is the best example because it follows the usual pattern: the base expansion name with an R suffix to denote reverse expansion. The other options don’t fit this standard naming pattern—placing the R at the start, using Reverse as a separate word, or rearranging the words to form ReverseTreeDescendants don’t align with how reverse expansions are conventionally named, so they aren’t recognized as the reverse variant.