In general, when analyzing structure you should ask yourself question including "A.What kind of text is it—a list, a paragraph, a report, a memo?" and "What is the theme or main idea of the piece of writing?" among others.
In Writing, structure shows the order of ideas and how different ideas linked together. Structure is one of the important aspects of academic writing. Lack of structure diverts the reader from the text. Repetition or linking unrelated ideas together shows the lack of the structure. Therefore, C and D are the most suitable answers to this question.
