The correct option is C China
The British forced an unequal treaty on China as they did with India, this is known as the The Convention of Beijing in 1860. What followed was an influx of Christian missioners into China who were at work in the Cantong region. This change of governmental power in China opened the door for the trade of opium and the beginning of the opium war. This opens the door for other western powers to take advantage of the Manchu Qing dynasty. In 1850, Hung starts a revolt that managed to have thousands of followers that went on to overthrow the weak Manchu Qing dynasty in a Civil war known as the Taiping Rebellion.