instruction:
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.
question:
Passage: The Gregorian calendar is a solar calendar. A regular Gregorian year consists of 365 days, but as in the Julian calendar, in a leap year, a leap day is added to February. In the Julian calendar a leap year occurs every 4 years, but the Gregorian calendar omits 3 leap days every 400 years. In the Julian calendar, this leap day was inserted by doubling 24 February, and the Gregorian reform did not change the date of the leap day. In the modern period, it has become customary to number the days from the beginning of the month, and February 29th is often considered as the leap day. Some churches, notably the Roman Catholic Church, delay February festivals after the 23rd by one day in leap years.
answer:
What calendar is a lunar calendar?


question:
Passage: Land-based steam engines could exhaust much of their steam, as feed water was usually readily available. Prior to and during World War I, the expansion engine dominated marine applications where high vessel speed was not essential. It was however superseded by the British invention steam turbine where speed was required, for instance in warships, such as the dreadnought battleships, and ocean liners. HMS Dreadnought of 1905 was the first major warship to replace the proven technology of the reciprocating engine with the then-novel steam turbine.[citation needed]
answer:
The frequent availability of what substance allowed land-based steam engines to exhaust a great deal of battleships?


question:
Passage: A German ethnicity emerged in the course of the Middle Ages, ultimately as a result of the formation of the kingdom of Germany within East Francia and later the Holy Roman Empire, beginning in the 9th century. The process was gradual and lacked any clear definition, and the use of exonyms designating "the Germans" develops only during the High Middle Ages. The title of rex teutonicum "King of the Germans" is first used in the late 11th century, by the chancery of Pope Gregory VII, to describe the future Holy Roman Emperor of the German Nation Henry IV. Natively, the term ein diutscher ("a German") is used for the people of Germany from the 12th century.
answer:

What ethnicity emerged following the Middle Ages?