What type of word adds detail to a verb, often ending in "ly"?

The choice of 'adverb' as the correct answer is appropriate because adverbs are specifically designed to modify verbs, providing additional detail about how, when, where, or to what extent an action is performed. Many adverbs do indeed end in "ly," which is a common suffix for this part of speech. For example, in the sentence "She runs quickly," the adverb "quickly" modifies the verb "runs" by explaining how she runs.

The other types of words listed do not serve the same function. Adjectives modify nouns, providing more information about a subject, but they do not add detail to verbs. Pronouns replace nouns and do not provide detailed modifications of actions. Articles serve a grammatical purpose by defining nouns but do not have the capability to modify verbs either. Therefore, the unique role of adverbs in enhancing the meaning of verbs makes them the correct answer in this context.