Correct Response: B. Sheltered English immersion (SEI) emphasizes differentiating content-area instruction to address students' varied linguistic needs. An SEI classroom can have English language learners at multiple levels of English language proficiency, and an emerging-level English language learner requires different scaffolds and supports than a bridging-level student. A is incorrect because research has shown that students require explicit instruction in academic language in order to develop the vocabulary and language skills needed to support content learning in a new language. C is incorrect because, while SEI teachers need to be cognizant of psychological factors affecting students' learning, the primary focus of SEI models is on students' development of content knowledge and academic language. D is incorrect because SEI promotes language development to support content learning; its focus is not exclusively on language development.