<span>C) :
A colon here is right to set up the quote from the introduction in the sentence. The lead in shows that the writer is about to provide a specific example, not a quote that continues the flow of the sentence. A colon allows the quote to stand alone from the rest of the sentence as an example.</span>
Hello. You did not present the excerpt to which this question refers, and you did not present the answer options. This makes your question impossible to answer. However, I will try to help you in the best possible way.
The central idea of a text is the main subject to which the text is addressing. It is the theme to which the author wishes to pass on reflection and reasoning. You will only be able to identify this idea with a complete reading of the passage to which your question refers, but you will be able to identify these ideas by the subject that the characters are addressing in their actions and speeches.
Descriptive is the answer
