The correct answer is B. Small Wars broke out in Europe soon after the Congress of Vienna.
While the Congress of Vienna and the Concert of Europe aimed to maintain peace and stability in Europe after the Napoleonic Wars, they did not entirely prevent conflicts. In fact, localized wars and tensions arose in various regions, indicating a limitation of their effectiveness in promoting long-term peace across the continent. The other options highlight positive aspects or outcomes of the Congress of Vienna and the Concert of Europe rather than negative impacts.