Answer:
i think the answer is C) Royal authority
Hello,
The answer the B. Taxes could be collected from citizens and used for the government.
Here is my reason why......
When the government grants citizenship you also have to pay taxes the government thinks its a good way to make money to help pay for daily services such as: Firefighter Stations, Police Stations, etc.... Particular services that help make life's easier.
Your answer is B.
If you need anymore help ask me. :)
Hope this helps you.
Oftentimes it is "removing barriers to trade" that motivates countries to join regional trade blocs, since members of such "blocks" have completely free trade with one another.