It could be considered as a key to the USA'S success. Back then we needed immigrants in order to build our nation. We were once immigrants to. So without the whole idea of immigration, the U.S might not have turned out as well as it did.
The answer would be C. Gold. Here's the definition <span> Nubian </span><span>nub </span><span>"gold."</span>
An oligarchy describes C. "rule by a small group". The size of this group can vary greatly but it relative to the size of the population its controlling and usually results and unfair governance.