D. It was leased to the British until 1997, when it became part of China again.
Explanation:
Hong Kong or officially the Hong Kong Special Administrative Region, is a special region of China that has existed since July 1997.
China ceded the island of Hong Kong to the United Kingdom in 1842 after the First Opium War. Subsequently, the English annexed the neighboring Kowloon peninsula and the many smaller islands around the colony, which in treaty were leased for 99 years, which could be renewed for an equal period. The colonial apparatus will make Hong Kong an impressive development for the next 150 years or so as an outpost of the British Far East empire, becoming a major business and commercial hub.
