what is the difference between sentence fluency and sentence variation? select one: a. sentence fluency is about how accurately the language is being used. sentence variation is how the accurate the grammar is applied. b. fluency is about how the sentences flow, and variation is about the word choice in the sentences. c. sentence fluency is about how the sentences sound and flow. variation is about the length of the sentences. d. sentence fluency is about the length of the sentence, and variation is about how the words flow in the sentence.