There is a total of 7 teachers, including a director, in a teaching and research office. Regarding these 7 staff members, only one of the following three conclusions is true: Ⅰ. Not that no one in the teaching and research office is from Shanghai.Ⅱ. The members of the teaching and researching office are not all Shanghainese Ⅲ. The director of the teaching and research office is not from Shanghai. Which of the following is true? [' teachers are from Shanghai.', ' teachers are not from Shanghai.', 'Only one person is not from Shanghai.', 'Only one person is from Shanghai.']