Answer:
C. a group of words that cannot stand alone as a sentence is a sentence fragment.
Step-by-step explanation:
A sentence fragment is an incomplete sentence that does not express a complete thought or idea. It is often missing a subject or a verb, or it may be a subordinate clause that cannot stand on its own. In order for a group of words to be considered a sentence, it must have both a subject and a verb and express a complete thought. A sentence fragment, on the other hand, is a group of words that does not meet these criteria and cannot stand alone as a sentence.