The correct answer is B. After the Chinese Civil War, the island of Taiwan became known as the Republic of China.
The Chinese Civil War ended in 1949 with an unofficial cessation of hostilities between the sides, with the mainland China (including Hainan Island) finally being controlled by the Communists, where the new regime of the People's Republic of China was proclaimed; while the nationalists managed to maintain control over the island territories of Taiwan, Phengu and several coastal islands of Fujian province, territories in which the regime of the Republic of China has been maintained until now.