During a group study, Nora wrote a statement on the board. Grace pointed out that it was a sentence fragment. What does that mean?

A. It means Nora expressed a complete thought with a subject and predicate

B. It means Nora wrote a group of words that lacks a subject, a predicate, or both

C. It means Nora wrote a sentence that is too long

D. It means Nora wrote a sentence with multiple subjects and predicates