The correct answer is: Only argument I is strong.
Argument I is strong because it is based on a logical reason. If there is a world government, then there will be a single authority to resolve disputes between nations. This would help to eliminate tensions and prevent wars.
Argument II is weak because it is based on an assumption. The assumption is that only the developed countries will dominate in a world government. However, there is no evidence to support this assumption. In fact, it is possible that a world government would be more democratic and representative than the current system of nation-states.
In conclusion, only argument I is strong. Argument II is weak because it is based on an assumption.