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>
