In which of the following sentences is an adverb used correctly? a. she sang beautifully. b. she sang the song beautiful. c. she is a beautifully singer. d. she sang a beautiful song.

The answer would be A: She sang beautifully. This would be the answer because this sentence is the only one that uses an adverb correctly. Adverbs describe a verb. An adverb describes when, where, or how an action is performed. In this case, the word beautifully describes how the girl sang. The other answers do not use an adverb correctly. Therefore, I believe sentence A. would be the correct answer.