Correct Response: C. Option C is correct because, by modeling how to use structural analysis and knowledge of familiar English morphemes to deduce the meaning of a new word (i.e., the root defense and the affixes in- and -ible), the teacher reinforces for students a powerful, independent word-learning strategy. Learning this strategy immediately extends students' understanding of the target word indefensible and, in the long term, promotes their ability to learn unfamiliar words that contain familiar morphemes. After using the strategy, the students should use context clues to verify that the meaning they have deduced makes sense in the text. Options A, B, and D are incorrect because they describe strategies that help students understand the meaning of a specific word, but they do not promote or extend the students' ongoing vocabulary development.