Correct Response: A. James Cummins's theory of common underlying proficiency (CUP) states that students who have learned academic concepts in their native language are able to apply this learning toward similar concepts in the target language. B is incorrect because it relates to errors in learning English rather than knowledge gained in a first language that can be applied in the target language. C is incorrect because it relates purely to language development rather than development of content knowledge. Similarly, D is incorrect because it relates to code-switching, a phenomenon related to language development and unrelated to concept development.