Correct Response: D. In the context of reading, structural analysis is the process of recognizing the morphemic structure of words. Typically, structural analysis is introduced to students in the early elementary grades as a strategy for identifying words with inflectional endings and common derivational prefixes and suffixes that are in students' oral vocabulary. The list in Option D features a phonically regular base word and affixes that are appropriate for beginning readers. The words pretest and retest both include a common prefix, while tested and testing include inflectional endings. Option A is incorrect because the words in this list contain only one morpheme and therefore are not useful for demonstrating structural analysis. Option B is incorrect because the list features words that contain prefixes and roots that are inappropriate for beginning instruction in structural analysis. Option C is incorrect because this list features a base word (swim) with irregular past tense forms (swam, swum). Such forms are inappropriate for introducing beginning readers to structural/morphemic analysis because the morpheme for past tense is indicated by a spelling change rather than by the more typical addition of an inflectional ending.