Parallel structure happens in this case when the list of items all has the same grammatical structure. The list of people first begins with the occupation (writer, orator, sculptor) and is then followed by the person's name (Isocrates, Demosthenes, Praxiteles). Options A and C do not include Praxiteles' occupation. Option B does tell you his occupation but it doesn't use the same grammatical structure. </span>
I think the answer is that Sarah should look up words she doesn't know for chapter titles, headings and first paragraphs and write the main idea in her own words.
