I believe the answer is D. Rewrite to keep a consistent tone. When we write, we write in sentences. Beginning with a capital letter, we wind our way over words and phrases until we've expressed a complete thought, and then we mark the an endpoint with a period, question mark, or exclamation mark. Readers read the same way: they follow the shape of each sentence from beginning to end trying to understand the single complete thought the writer is expressing. In order for readers to do that, your writing needs to flow smoothly from word to word, phrase to phrase, and sentence to sentence.