I believe d. be in something easy to carry.
It should have at least 4
They shared cultural ties, especially in language.
You can say something about paying taxes, as that help the government build and improve infrastructure. (roads, buildings, etc)
You can also say something about voting as that tells the government to know what they need to improve on, and what the people want. (not just for candidates)
B. environment of evolutionary adaptedness.
