The correct answer is B. This is because it offers a detail in relation to the main idea, whereas the other options do not.
Hope this helps.
Teachers are not as much smarter as professors. Professors know more than teachers and in the word "professor" there is a word "pro" in it which means professional. So, the teachers teach mathematics for the most. But unless they are trained. They only know one subject per class. Such as moving classes in middle school, high school, and collage. You are moving to different subjects, different teachers, different lessons. And a professor teaches more than one subject. They teach: Science, mathematics, art, social studies, and many other than one teacher.
The answer is True that the author's selections give unity to his novel.
