
Passage: Wang Gang must be a university teacher because he not only has a doctorate from a famous university, but also has more than a year of research experience in an overseas research institution.
Question: Which of the followings can guarantee the correctness of the above statement?
A. A.Unless you are a university teacher, it is impossible to have a doctorate from a prestigious university and more than one year of research experience in an overseas research institution
B. B.In recent years, university teachers are required to have overseas research experience
C. C.Some middle school teachers also have doctorates and overseas research experience
D. D.Unless he/she is a doctor and has more than one year of overseas research experience, he/she cannot become a university teacher
Answer: