Test Analysis: This question mainly examines students' accurate memory of treaty of nanking. Pay attention to "Emperor Guangdi (1821-Kloc-0/850 reigned)" and "Defeat" when solving problems, that is, China was defeated in the Opium War and signed the treaty of nanking, which stipulated in the treaty that Hong Kong Island was cut to Britain. According to the analysis, D meets the meaning of the question, so D is chosen.