The correct answer is Option D.
After mentioning the main idea of the paragraph, the next step that follows is the illustration of the topic and the main idea. This is done by providing supporting explanation through examples, statistical data and other supporting details. Thus, option A, B, and C are the incorrect options since the question is what is NOT a part of the illustration of the topic.
The topic sentence (Option D) is the directing force of the paragraph and not a part of the illustration of the topic. Hence Option D is the correct option.