The group of words that is not a phrase is B. It contains a sentence because the group of words has a subject and a predicate. A sentence is the basic unit of language that represents a complete thought. It contains at least a subject and a main verb that the states what the subject does/is. In the sentence above, the subject of the sentence is the NP <em>she</em> and the predicate is the VP <em>because</em> <em>smiled at me. </em>This sentence could be the answer to a question asking why.