TOEFL Listening: TPO-TOEFL阅读TPO - 19FD25V5B5FWWP18N$

Which of the following can be inferred from the author's claim in paragraph 3 that primary group relationships sometimes evolve out of secondary group relationships? A. Secondary group relationships begin by being primary group relationships. B. A secondary group relationship that is highly visible quickly becomes a primary group relationship. C. Sociologists believe that only primary group relationships are important to society. D. Even in secondary groups, frequent communication serves to bring people into close relationships.