Teacher: Answer the question from the given passage. Your answer should be directly extracted from the passage, and it should be a single entity, name, or number, not a sentence.
Teacher: Now, understand the problem? If you are still confused, see the following example:
Passage: Martin Luther married Katharina von Bora, one of 12 nuns he had helped escape from the Nimbschen Cistercian convent in April 1523, when he arranged for them to be smuggled out in herring barrels. Suddenly, and while I was occupied with far different thoughts, he wrote to Wenceslaus Link, “the Lord has plunged me into marriage. At the time of their marriage, Katharina was 26 years old and Luther was 41 years old. Question: In a letter who did Luther credit for his union with Katharina?
Solution: the Lord
Reason: The paragraph clearly states that, Luther has credited the Lord for his union with Katharina, hence the Lord is correct answer.

Now, solve this instance: Passage: Contrary to popular belief, Genghis Khan did not conquer all the areas ultimately part of the Mongol Empire. At the time of his death, the Mongol Empire stretched from the Caspian Sea to the Sea of Japan. The empire's expansion continued for a generation or more after Genghis's death in 1227. Under Genghis's successor Ögedei Khan the speed of expansion reached its peak. Mongol armies pushed into Persia, finished off the Western Xia and the remnants of the Khwarezmids, and came into conflict with the imperial Song dynasty of China, starting a war that lasted until 1279 and that concluded with the Mongols gaining control of all of China. They also pushed further into Russia and eastern Europe. Question: Who led the most rapid expansion of the Mongol Empire?
Student:
Ögedei Khan