Answer:
When authors want to communicate an idea to a reader, they may state the general idea and then make it clear through the use of illustrations and examples.
C. illustrations and examples
Step-by-step explanation:
The main aim of writing any text is to convey the idea of the author to the reader. The writing needs to be explanatory and informative so that the reader can infer what the writer wants to convey through it. The illustrations and examples help the writer to make his point clear to the reader.