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: Shell's primary business is the management of a vertically integrated oil company. The development of technical and commercial expertise in all stages of this vertical integration, from the initial search for oil (exploration) through its harvesting (production), transportation, refining and finally trading and marketing established the core competencies on which the company was founded. Similar competencies were required for natural gas, which has become one of the most important businesses in which Shell is involved, and which contributes a significant proportion of the company's profits. While the vertically integrated business model provided significant economies of scale and barriers to entry, each business now seeks to be a self-supporting unit without subsidies from other parts of the company.

SOLUTION: What is the least important business for Shell?

PROBLEM: Passage: Literature allows readers to access intimate emotional aspects of a person’s character that would not be obvious otherwise. It benefits the psychological development and understanding of the reader. For example, it allows a person to access emotional states from which the person has distanced himself or herself. An entry written by D. Mitchell featured in ‘‘The English Journal’’ explains how the author utilized young adult literature in order to re-experience the emotional psychology she experienced as a child which she describes as a state of “wonder”.

SOLUTION: What gives readers access to physical aspects of a character?

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?