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.
It was one of the reasons the US joined the war. With that, the Germans and Central Power started to lose (they had no chances after the sinking and the Zimmermann telegram)
Many of the ballots could not be read by the machine so The Florida supreme court ordered a manual recount which was stopped and ruled unconstitutional by The United states supreme court.
