(A) 1990
(B) 1991
(C) 2002
(D) 2001
🧠 Explanation:
- China officially joined the World Trade Organization (WTO) on **December 11, 2001** after years of negotiation.
- This membership marked a major step in China's integration into the global economy.
- Joining the WTO allowed China to expand trade, attract foreign investment, and adopt international trade rules.
- Options like 1990, 1991, and 2002 are incorrect — the exact year was **2001**.