instruction:
In this task, you are given a question and a context passage. You have to answer the question based on the given passage.
question:
who avenged Chu'Tsai's forefathers?, Context: Genghis Khan realised that he needed people who could govern cities and states conquered by him. He also realised that such administrators could not be found among his Mongol people because they were nomads and thus had no experience governing cities. For this purpose Genghis Khan invited a Khitan prince, Chu'Tsai, who worked for the Jin and had been captured by the Mongol army after the Jin dynasty was defeated. Jin had captured power by displacing Khitan. Genghis told Chu'Tsai, who was a lineal descendant of Khitan rulers, that he had avenged Chu'Tsai's forefathers. Chu'Tsai responded that his father served the Jin dynasty honestly and so did he; also he did not consider his own father his enemy, so the question of revenge did not apply. This reply impressed Genghis Khan. Chu'Tsai administered parts of the Mongol Empire and became a confidant of the successive Mongol Khans.
answer:
Genghis Khan

question:
Who has studied the Mahayana?, Context: There is no evidence that Mahayana ever referred to a separate formal school or sect of Buddhism, but rather that it existed as a certain set of ideals, and later doctrines, for bodhisattvas. Initially it was known as Bodhisattvayana (the "Vehicle of the Bodhisattvas"). Paul Williams has also noted that the Mahayana never had nor ever attempted to have a separate Vinaya or ordination lineage from the early schools of Buddhism, and therefore each bhiksu or bhiksuni adhering to the Mahayana formally belonged to an early school. This continues today with the Dharmaguptaka ordination lineage in East Asia, and the Mulasarvastivada ordination lineage in Tibetan Buddhism. Therefore Mahayana was never a separate rival sect of the early schools. From Chinese monks visiting India, we now know that both Mahayana and non-Mahayana monks in India often lived in the same monasteries side by side.
answer:
Paul Williams

question:
What does the second D in DVD mean?, Context: The only cosmetic difference between an RLV disc and a regular factory-pressed LaserDiscs is their reflective purple-violet (or blue with some RLV discs) color resulting from the dye embedded in the reflective layer of the disc to make it recordable, as opposed to the silver mirror appearance of regular LDs. The purplish color of RLVs is very similar to DVD-R and DVD+R discs. RLVs were popular for making short-run quantities of LaserDiscs for specialized applications such as interactive kiosks and flight simulators.
answer:
disc