The main idea is the central message that's communicated by a writer or speaker, or author.
Central idea is the main idea of the content or essay, in which all the text or story revolves around it. Central idea is the backbone of the essay that has mainly focused on, but the central idea is written at the end of the essay so that it gives a clear understanding.
Thus, option C is correct.
For more details about Central idea, click here:
https://brainly.com/question/11224750
#SPJ2