Some teaching and research office will send some teachers to participate in an international academic seminar. According to the work arrangement, Which of the following conditions must be met: (1) If Mr. Zhao or Qian is going, then Sun should also go; Must go; (3) If Teacher Qian does not go, then Teacher Li goes, but Teacher Zhou cannot go; (4) If Director Zong goes, then Teacher Zhou should also go. From this. ['Teacher Qian, Teacher Sun should go.', 'Teacher Qian and Teacher Sun should not go.', 'Teacher Qian should go, Teacher Sun should not go.', 'Teacher Sun should go, Teacher Qian should not go.']