Which of the following choices is a correlative conjunction?

The choice that represents a correlative conjunction is "Both-and." Correlative conjunctions are pairs of conjunctions that work together to join words, phrases, or clauses that are related. They emphasize a relationship and create a balanced connection between the elements they link.

"Both-and" specifically connects two nouns, verbs, or other grammatical elements, showing that they are to be considered together within the same context. For example, in the sentence "Both the teacher and the student were present," "both-and" effectively links the teacher and the student as equally relevant subjects.

In contrast, the other choices do not function as correlative conjunctions. "Although" and "unless" serve as subordinating conjunctions, which introduce dependent clauses and indicate conditions or contrast but do not operate in pairs. "Because" is also a subordinating conjunction that explains reasons but does not join equal parts of a sentence in the way that correlative conjunctions do. Recognizing the specific role of conjunction types helps in constructing clear and effective sentences.