Concept:The WTO manages global trade rules to keep international trade free and open.
Explanation:The World Trade Organization (WTO) sets and enforces rules that guide trade between countries.
Its main role is to make trade flow smoothly, predictably, and freely.
It works to lower tariffs, remove unfair barriers, and settle trade disputes.
These efforts directly reduce obstacles to international trade and investment.
The WTO does not control oil prices, guarantee equal participation, or modernise world economies.
Answer:D. minimizing obstacles to international trade and investment.