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: Until the Church Building Act of 1818, the period saw relatively few churches built in Britain, which was already well-supplied, although in the later years of the period the demand for Non-conformist and Roman Catholic places of worship greatly increased. Anglican churches that were built were designed internally to allow maximum audibility, and visibility, for preaching, so the main nave was generally wider and shorter than in medieval plans, and often there were no side-aisles. Galleries were common in new churches. Especially in country parishes, the external appearance generally retained the familiar signifiers of a Gothic church, with a tower or spire, a large west front with one or more doors, and very large windows along the nave, but all with any ornament drawn from the classical vocabulary. Where funds permitted, a classical temple portico with columns and a pediment might be used at the west front. Decoration inside was very limited, but churches filled up with monuments to the prosperous.

SOLUTION: What act slowed the building of churches in Britain?

PROBLEM: Passage: There were 112,608 households in the city in 2000, of which 26.5% included children below the age of 18, 39.5% were composed of married couples living together, 11.4% reported a female householder with no husband present, and 45.5% classified themselves as nonfamily. Unmarried partners were present in 2.2% of households. In addition, 33.1% of all households were composed of individuals living alone, of which 6.2% was someone 65 years of age or older. The average household size in Raleigh was 2.30 persons, and the average family size was 2.97 persons.

SOLUTION: How many households were there in 2001?

PROBLEM: Passage: Following the purchase of an offshore lease in 2005, Shell initiated its US$4.5 billion Arctic drilling program in 2006, after the corporation purchased the "Kulluk" oil rig and leased the Noble Discoverer drillship. At inception, the project was led by Pete Slaiby, a Shell executive who had previously worked in the North Sea. However, after the purchase of a second offshore lease in 2008, Shell only commenced drilling work in 2012, due to the refurbishment of rigs, permit delays from the relevant authorities and lawsuits. The plans to drill in the Arctic led to protests from environmental groups, particularly Greenpeace; furthermore, analysts in the energy field, as well as related industries, also expressed skepticism due to perceptions that drilling in the region is "too dangerous because of harsh conditions and remote locations".

SOLUTION:
How much did the purchase of an offshore lease cost?