(A) 1955
(B) 1949
(C) 1950
(D) 1951
🧠 Explanation:
- Taiwan separated from mainland China in **1949**, after the Chinese Civil War ended.
- The Communist Party, led by Mao Zedong, took control of mainland China and established the **People's Republic of China**.
- The defeated **Nationalist Party (Kuomintang)** fled to Taiwan and continued to operate as the **Republic of China**.
- Since this major political split occurred in 1949, the correct answer is (B).