Which search broadening option in FTK allows you to find grammatical variations of words?

Stemming is the search broadening option in FTK that enables users to find grammatical variations of words by reducing words to their root form. For example, stemming would allow a search for the term "running" to also return results for "run," "runner," and "ran". This is particularly useful in forensic investigations where documents may contain different tenses or forms of a word, and it ensures that important information is not overlooked due to variations in word usage.

In contrast, synonyms focus on different words with similar meanings; truncation involves shortening words to capture all terms that start with a particular root; and rooting, while it may sound similar to stemming, is not a recognized search option in FTK. Therefore, stemming stands out as the option specifically designed to address grammatical variations, making it the correct answer in this context.