which of the following describes a major achievement of the mongol empire?

Ait repeatedly defeated the powerful roman army in battle.
Bit oversaw a thriving economy despite having little interest in supporting trade.
Cit established a unified culture and religion throughout all of Asia.
Dit became the first foreign country to rule all of China.

The Mongol empire, was the second largest empire in history and the largest empire constituted by continuous territories. It was founded by Genghis Khan in the year 1206 and had its peak when it reached 24,000,000 km². It came to encompass a territory from the Korean peninsula to the Danube River, to host a population of more than 100 million inhabitants and to include some regions as rich and important as China, Mesopotamia, Persia, Eastern Europe, Russia, among others.

After the death of Genghis in the year 1227, his successors, under the second jan, Ogodei, continued the expansion. This expansion included Persia, ended the Xia and the remains of the corasmios, and led to a conflict with the Song Dynasty of southern China, beginning a war that did not end until the year 1279 in which there was the total occupation of the country and the reunification of the government of China under the Mongols. At the end of the 1230s, the Mongols, under the command of Batu Khan, invaded Russia, killing about half of the local population, and then reducing most of their principalities to vassalage.