According to Fr. Sullivan the word authentic here means authoritative. The word authentic should not be understood as genuine. So bishops and pope teach with authority and we have to obey. This expression also shows the source of authority for this authentic teaching namely Jesus Christ (cf. LG 25; DV 10). If we take the meaning only as genuine then it will lead us to think only the bishops can give a genuine interpretation of the Word of God. This does not mean also that nobody in the Church other than the bishops can speak with authority. The theologians and the exegete can speak with authority which their expertise confers on them. Perhaps what the Council exclusively attributed to the living magisterium is the pastoral authority to teach the Gospel in the name of Jesus Christ.