This task is about creating an unanswerable question based on a given passage. Construct a question that looks relevant to the given context but is unanswerable. Following are a few suggestions about how to create unanswerable questions:
(i) create questions which require satisfying a constraint that is not mentioned in the passage
(ii) create questions which require information beyond what is provided in the passage in order to answer
(iii) replace an existing entity, number, date mentioned in the passage with other entity, number, date and use it in the question
(iv) create a question which is answerable from the passage and then replace one or two words by their antonyms or insert/remove negation words to make it unanswerable.

Passage: The average Mongol garrison family of the Yuan dynasty seems to have lived a life of decaying rural leisure, with income from the harvests of their Chinese tenants eaten up by costs of equipping and dispatching men for their tours of duty. The Mongols practiced debt slavery, and by 1290 in all parts of the Mongol Empire commoners were selling their children into slavery. Seeing this as damaging to the Mongol nation, Kublai in 1291 forbade the sale abroad of Mongols. Kublai wished to persuade the Chinese that he was becoming increasingly sinicized while maintaining his Mongolian credentials with his own people. He set up a civilian administration to rule, built a capital within China, supported Chinese religions and culture, and devised suitable economic and political institutions for the court. But at the same time he never abandoned his Mongolian heritage.
By what year was selling children into slavery uncommon among the Mongols?

Passage: In 1607, English Chief Justice Sir Edward Coke said in the Case of Prohibitions (according to his own report) "that the law was the golden met-wand and measure to try the causes of the subjects; and which protected His Majesty in safety and peace: with which the King was greatly offended, and said, that then he should be under the law, which was treason to affirm, as he said; to which I said, that Bracton saith, quod Rex non debed esse sub homine, sed sub Deo et lege (That the King ought not to be under any man but under God and the law.)."
Who called the law a golden met-wand during the sixteenth century?

Passage: The city's charter was granted by Prince John, as Lord of Ireland, in 1185. The city was once fully walled, and some wall sections and gates remain today. For much of the Middle Ages, Cork city was an outpost of Old English culture in the midst of a predominantly hostile Gaelic countryside and cut off from the English government in the Pale around Dublin. Neighbouring Gaelic and Hiberno-Norman lords extorted "Black Rent" from the citizens to keep them from attacking the city. The present extent of the city has exceeded the medieval boundaries of the Barony of Cork City; it now takes in much of the neighbouring Barony of Cork. Together, these baronies are located between the Barony of Barrymore to the east, Muskerry East to the west and Kerrycurrihy to the south.
What was Prince John Lord of in the 11th century?