What was the most important side effects of the mongol invasion

The invasions of the Mongols occurred throughout the thirteenth century, resulting in the vast Mongol Empire, which included much of Asia and Eastern Europe. It represents the deadliest conflicts in human history. The Mongols induced the displacement of the population in particular in Central Asia and Eastern Europe. They had a great influence on the history of the world. they invaded China and forced Korea to become a vassal after an invasion of Korea. His greatest triumph was the creation of his own Yuan dynasty in China. They annihilated all the major cities of Eastern Europe with the exception of Novgorod and Pskov. They attacked Rus, where they made great havoc, destroying cities and fortresses and sacrificial men, and placed siege to Kiev, the capital of Rus. Meanwhile, many other countries became vassal states or tributary states of the Mongol Empire.

Perhaps saving more money for their retirement and getting better life insurance for jackie. and trying to spend less money on unnecessary expenses always . 

The answer might be c