When one reads "the real purpose of the Congress was to divide amongst the conquerors the spoils taken from the vanquished." It is quite simple to interpret the Words of Gentz to simply answer that the True purpose of the Congress of Vienna was:
4. to divide Europe among powerful monarchs
So the Answer to this question is option 4
Religion. Religion effects what products are sold (a Jewish or Islamic government will not sell pork in the marketplace.) In the Middle ages, the citizens of most European Countries thought that the King was chosen by God, so whatever that King issued was in essence the word of God. Religion also effects things like women's prominence in a community, the acceptance of diversity, and how a country views the ideas of warfare vs. pacifism.
To ensure future trade with european countries and to help economic growth