According to the inquiry, if we want to "save China and build a harmonious society, we must first carry out an ideological revolution." It was () who first advocated and blew the horn of ideological enlightenment. A. Cai Yuanpei; B. Chen Duxiu; C. Liu Bannong; Ting Qian. Answer: B. Chen Duxiu.

This question mainly examines the famous sayings in the modern history of China, which belongs to the basic memory question and requires candidates to have rich historical knowledge. "To save China and build a harmonious society, we must first carry out an ideological revolution." This sentence was said by Chen Duxiu.