As an Example of How Virtually No One Is Immune

As an example of how virtually no one is immune from larger political and economic forces, the Yanomami tribal society of Brazil has suffered recent changes as a result of

A) being overrun by the more expansion-minded Nilotic peoples.
B) modern-minded big men amassing so much wealth that people have begun to regard them as chiefs.
C) village raiding among tribal groups.
D) the involvement of NGOs in their internal political affairs.
E) encroachment by gold miners and cattle ranchers.