C. because it is a side comment that they like the restaurant best, it is not part of the actual statement. Which is "The restaurant is open 14 hours a day"
"That I like best" is an essential relative clause, so it should not be offset with commas from the rest of the sentence. It can't be removed without altering the meaning of the sentence, it is essential to its understanding. If it was left out, the reader would not know which restaurant the speaker is talking about. The relative clauses introduced with "that" aren't nonessential, their information is always important to the meaning of the sentence and are therefore never punctuated with commas.
During which part of the writing process should a writer do research to gather evidence? A student should conduct research for an essay to gather the , or the details that show that the student's essay is true.
