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: Historians have divided the history of Cubism into phases. In one scheme, the first phase of Cubism, known as Analytic Cubism, a phrase coined by Juan Gris a posteriori, was both radical and influential as a short but highly significant art movement between 1910 and 1912 in France. A second phase, Synthetic Cubism, remained vital until around 1919, when the Surrealist movement gained popularity. English art historian Douglas Cooper proposed another scheme, describing three phases of Cubism in his book, The Cubist Epoch. According to Cooper there was "Early Cubism", (from 1906 to 1908) when the movement was initially developed in the studios of Picasso and Braque; the second phase being called "High Cubism", (from 1909 to 1914) during which time Juan Gris emerged as an important exponent (after 1911); and finally Cooper referred to "Late Cubism" (from 1914 to 1921) as the last phase of Cubism as a radical avant-garde movement. Douglas Cooper's restrictive use of these terms to distinguish the work of Braque, Picasso, Gris (from 1911) and Leger (to a lesser extent) implied an intentional value judgement.
What was the last phase of Cubism known as?

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.
What calendar is a lunar calendar?

Passage: Countries in the top quartile of HDI ("very high human development" group) with a missing IHDI: New Zealand, Singapore, Hong Kong, Liechtenstein, Brunei, Qatar, Saudi Arabia, Andorra, United Arab Emirates, Bahrain, Cuba, and Kuwait.
Which Caribbean nation is in the top quartile of HIDI (but missing HIHDI)?