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.

Example Input: Passage: Min Nan texts, all Hokkien, can be dated back to the 16th century. One example is the Doctrina Christiana en letra y lengua china, presumably written after 1587 by the Spanish Dominicans in the Philippines. Another is a Ming Dynasty script of a play called Romance of the Lychee Mirror (1566), supposedly the earliest Southern Min colloquial text. Xiamen University has also developed an alphabet based on Pinyin, which has been published in a dictionary called the Minnan Fangyan-Putonghua Cidian (閩南方言普通話詞典) and a language teaching book, which is used to teach the language to foreigners and Chinese non-speakers. It is known as Pumindian.
Example Output: Who has developed an alphabet based on Pumindian?

Example Input: Passage: The city's municipal government was dominated by about 12–15 merchant families, whose wealth came from overseas trade with continental Europe — in particular the export of wool and hides and the import of salt, iron and wine. The medieval population of Cork was about 2,100 people. It suffered a severe blow in 1349 when almost half the townspeople died of plague when the Black Death arrived in the town. In 1491, Cork played a part in the English Wars of the Roses when Perkin Warbeck a pretender to the English throne, landed in the city and tried to recruit support for a plot to overthrow Henry VII of England. The then mayor of Cork and several important citizens went with Warbeck to England but when the rebellion collapsed they were all captured and executed. The title of Mayor of Cork was established by royal charter in 1318, and the title was changed to Lord Mayor in 1900 following the knighthood of the incumbent Mayor by Queen Victoria on her Royal visit to the city.
Example Output: How many aristocratic families dominated the government?

Example Input: Passage: Glass has the ability to refract, reflect, and transmit light following geometrical optics, without scattering it. It is used in the manufacture of lenses and windows. Common glass has a refraction index around 1.5. This may be modified by adding low-density materials such as boron, which lowers the index of refraction (see crown glass), or increased (to as much as 1.8) with high-density materials such as (classically) lead oxide (see flint glass and lead glass), or in modern uses, less toxic oxides of zirconium, titanium, or barium. These high-index glasses (inaccurately known as "crystal" when used in glass vessels) cause more chromatic dispersion of light, and are prized for their diamond-like optical properties.
Example Output:
What can be used to make glass less dense?