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.

[EX Q]: Passage: In 1906, the tungsten filament was introduced. Tungsten metal was initially not available in a form that allowed it to be drawn into fine wires. Filaments made from sintered tungsten powder were quite fragile. By 1910, a process was developed by William D. Coolidge at General Electric for production of a ductile form of tungsten. The process required pressing tungsten powder into bars, then several steps of sintering, swaging, and then wire drawing. It was found that very pure tungsten formed filaments that sagged in use, and that a very small "doping" treatment with potassium, silicon, and aluminium oxides at the level of a few hundred parts per million greatly improved the life and durability of the tungsten filaments.
[EX A]: What was introduced in 1900?

[EX Q]: Passage: As with most of Europe, prehistoric Britain and Ireland were covered with forest and swamp. Clearing began around 6000 BC and accelerated in medieval times. Despite this, Britain retained its primeval forests longer than most of Europe due to a small population and later development of trade and industry, and wood shortages were not a problem until the 17th century. By the 18th century, most of Britain's forests were consumed for shipbuilding or manufacturing charcoal and the nation was forced to import lumber from Scandinavia, North America, and the Baltic. Most forest land in Ireland is maintained by state forestation programmes. Almost all land outside urban areas is farmland. However, relatively large areas of forest remain in east and north Scotland and in southeast England. Oak, elm, ash and beech are amongst the most common trees in England. In Scotland, pine and birch are most common. Natural forests in Ireland are mainly oak, ash, wych elm, birch and pine. Beech and lime, though not native to Ireland, are also common there. Farmland hosts a variety of semi-natural vegetation of grasses and flowering plants. Woods, hedgerows, mountain slopes and marshes host heather, wild grasses, gorse and bracken.
[EX A]: Ice and snow covered prehistoric Britain and what other country?

[EX Q]: Passage: Bethencourt took the title of King of the Canary Islands, as vassal to Henry III of Castile. In 1418, Jean's nephew Maciot de Bethencourt sold the rights to the islands to Enrique Pérez de Guzmán, 2nd Count de Niebla.
[EX A]:
What title did Henry II take in the Canary Island?