Mostly, the Europeans dominated because their numbers or military technology and organization were superior.
Considering the alternatives, the only alternative that represents any sort of military power being evolved with it is:
d. They built infrastructure to keep military units traveling and intimidating the locals.
Also, the British and other countries did build many railroads in Africa.
The answer is: People surrender some of their natural rights in exchange for the common good
Both Rousseau and Locke theorized about the Social contract which is a type of agreement between the people and the legitimate powers of authority that results in the formation of a<u> state or an organized society</u>, the prime motive being the desire for protection, and in order to achieve this common good they had to be willing to forfeit some of their rights and impose the same duties on all.
By killing the whiteys, of course! HaHa!
The Confederation System.
The Confederation System had a loose relationship with other political units or the states that existed within the country at the moment, such as federal governments.
Hope this helps!