1. 上嘴唇的淋巴回流到: (A) 下頜下淋巴結 (submandibular nodes) (B) 頰下淋巴結 (submental nodes) (C) 舌骨下淋巴結 (infrahyoid nodes) (D) 頸淺淋巴結 (superficial cervical nodes)