79. Which of the following statements about “Nanguan” is correct？ (A) The historical origin of Nanguan can be traced back to the Qing-Shang(清商) music in the Han Dynasty. (B) The pipa, which was played vertically in Tang Dynasty, is also the foundation of Nanguan. (C) Based on the Tang Music Ensemble System, most of them start with wind instruments and then add plucking (D) The characteristics of the Tang Dynasty Daqu can be seen in the pure instrumental music of Nanguan