What is a word that can function independently as a noun phrase?

A pronoun stands out as the correct answer because it has the ability to act independently as a noun phrase. Pronouns are words that can replace nouns and, in doing so, refer to people, places, or things without needing additional modifiers. For instance, words like "she," "they," and "it" can stand alone and convey complete meaning in context.

In contrast, the other options do not function independently as noun phrases. A verb serves as an action word but cannot replace a noun or act alone as a noun phrase. An adjective describes a noun but does not serve the function of a noun itself. An adverb modifies verbs, adjectives, or other adverbs but likewise does not have the capacity to function as a noun. Therefore, the unique capacity of pronouns to stand alone and represent nouns is what makes it the correct choice in this context.