Which country controlled Hong Kong before it was returned to China?

The country that controlled Hong Kong before its return to China in 1997 was Great Britain. The British took control of Hong Kong in 1842 after the First Opium War, formalized by the Treaty of Nanking, which ceded the island to Britain. Over the next century and beyond, Hong Kong developed into a bustling port and a significant economic center under British rule. This colonial administration continued until the 1997 handover, when sovereignty over Hong Kong was transferred back to China under the principle of "one country, two systems," allowing for a degree of autonomy.

While Japan occupied Hong Kong during World War II (1941-1945), this period was brief, and post-war, the British resumed control. The United States has never had sovereignty over Hong Kong, and Korea, divided into North and South after World War II, is not related to the historical governance of Hong Kong. Thus, the correct answer is Great Britain, as it held control for the longest duration prior to the return to Chinese sovereignty.