Answer: B
Implied powers are ones that the federal government has but they are not written in the Constitution of the US
The correct answer in my opinion would be that D is the most important factor here. But this question is quite tricky.
We can surely say for example that literature, organized schools and a hierarchy of priests are not something that constitute a civilization. Organized schools appeared to late, not every civilization had literature and having only a hierachy of priests is not enough to say you have a civilizaton.
Labor has been divided in pre-civilization hunter-gatherer societies as well.
For that reason I'd say the correct answer is D - more food than is needed for survival. Having this, the people in a certain group can focus on other things.
I figure gold prospectors only because the gold rush had happened over in California I believe?