TASK DEFINITION: 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.
PROBLEM: 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.

SOLUTION: Ice and snow covered prehistoric Britain and what other country?

PROBLEM: Passage: The name of the metal was probably first documented by Paracelsus, a Swiss-born German alchemist, who referred to the metal as "zincum" or "zinken" in his book Liber Mineralium II, in the 16th century. The word is probably derived from the German zinke, and supposedly meant "tooth-like, pointed or jagged" (metallic zinc crystals have a needle-like appearance). Zink could also imply "tin-like" because of its relation to German zinn meaning tin. Yet another possibility is that the word is derived from the Persian word سنگ seng meaning stone. The metal was also called Indian tin, tutanego, calamine, and spinter.

SOLUTION: Who is attributed as the only person to document zinc?

PROBLEM: Passage: There is ongoing debate about whether central banks should target zero inflation (which would mean a constant value for the U.S. dollar over time) or low, stable inflation (which would mean a continuously but slowly declining value of the dollar over time, as is the case now). Although some economists are in favor of a zero inflation policy and therefore a constant value for the U.S. dollar, others contend that such a policy limits the ability of the central bank to control interest rates and stimulate the economy when needed.

SOLUTION:
What would zero inflation mean for control interest over time?