In this task, you're given a passage, further information available on a particular linked term from the statement, and an answer term. Your job is to generate a question that can use the information provided to obtain the given answer. You should use the information on both passage and link information to create the question. Note that the answer to the question should be exactly the given answer, and if the answer is none, the answer to the question shouldn't be obtainable from the passage or linked information.

Q: Passage: Since about 560, the Avars had ruled over large parts of the Pannonian Basin and Carantania southeast of Francia, though in the last decades, the Avar Khaganate had to deal with Bulgarian and Croat incursions. To secure the frontier of his empire and the traffic on the trade routes to the east, Charlemagne allied with Khan Krum of Bulgaria and the Croatian duke Vojnomir, and from 791 launched several campaigns against the Avars, where he, according to the Vita Karoli Magni, encountered only modest opposition. In 796 Carolingian forces under Charlemagne's son Pepin of Italy destroyed the main Avar fortress called the Ring of the Avars and made the Khagan a Frankish vassal, while the remaining Avars retreated behind the Tisza River. The victory is perpetuated by the poem De Pippini regis Victoria Avarica. 
 Link Information: Pepin or Pippin (or Pepin Carloman, Pepinno, April 773 – 8 July 810) Answer: 23

A: How old was Charlemagne's son when he destroyed the Ring of the Avars?
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Q: Passage: After the Nazis came to power, he emigrated to Switzerland in 1933 and to the United States later. He began his studies in Zurich and worked part-time as a house teacher. Meanwhile, he wrote articles and book reviews for the Neue Zürcher Zeitung, using several pseudonyms because of prohibition of work. He earned his PhD and taught French and German Literature at various universities, including Princeton University and University of Wisconsin-Madison. During a journey to Europe, Vordtriede was surprised by the outbreak of the Second World War and interned as an Enemy alien in occupied France. By interventions, he became free months later and was allowed to go back to America. He met his mother in New York City late in 1941, who also emigrated to the USA. He received the American citizenship in 1946 and became a Guggenheim Fellow in 1957. His sister Fränze emigrated in 1947 and went to Philadelphia.
 Link Information:  Zürich. The municipality has approximately 409,000 inhabitants, the urban agglomeration 1.315 million and the Zürich metropolitan area 1.83 million Answer: metropolitan area 1.83 million

A: What is the population of the city where Vordtriede once studied and worked as a teacher?
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Q: Passage: Jiang Ji (died 18 May 249), courtesy name Zitong, was an official and military general of the state of Cao Wei during the Three Kingdoms period of China. Born in the late Eastern Han dynasty, Jiang Ji started his career as a low-level official in his native Yang Province before becoming a subordinate of Cao Cao, the warlord who controlled the central government towards the end of the Eastern Han dynasty. After the end of the Eastern Han dynasty, he served in the state of Cao Wei through the reigns of the first three emperors – Cao Pi, Cao Rui and Cao Fang – and held various appointments in the military before rising to Grand Commandant, one of the top positions in the central government. During his service in Wei, he was known for being candid in giving advice to the emperor on various issues, including consolidating power, halting labour-intensive construction projects, and officials' abuses of power. In February 249, he joined the regent Sima Yi in staging a successful coup d'état against his co-regent Cao Shuang, but died from illness a few months later.
 Link Information: The Incident at the Gaoping Tombs was a coup d'état that took place on 5 February 249 in the state of Cao Wei during the Three Kingdoms period (220–280) of China. The parties involved were Sima Yi and Cao Shuang, Answer: the state of Cao Wei

A:
What was the site of the successful military operation Ji staged against a co-regent?
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