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.

Passage: The so-called "Sack of Palermo" is one of the major visible faces of the problem. The term is used to indicate the speculative building practices that have filled the city with poor buildings. The reduced importance of agriculture in the Sicilian economy has led to a massive migration to the cities, especially Palermo, which swelled in size, leading to rapid expansion towards the north. The regulatory plans for expansion was largely ignored in the boom. New parts of town appeared almost out of nowhere, but without parks, schools, public buildings, proper roads and the other amenities that characterise a modern city.
What is the term for the building boom erected many fine buildings?

Passage: The school has many nationally and internationally acclaimed scholars in social security, health care, health disparities, communication, social and health policy, and individual and family development. Many of the faculty have training in both social work and public health. The school's current dean is Edward F. Lawlor. In addition to affiliation with the university-wide Institute of Public Health, Brown houses 12 research centers. The Brown School Library collects materials on many topics, with specific emphasis on: children, youth, and families; gerontology; health; mental health; social and economic development; family therapy; and management. The library maintains subscriptions to over 450 academic journals.
How many academic journal subscriptions does the Brown School Library have for mental health issues?

Passage: The Industrial Revolution in the Midlands and Northern England spelled the end for most of Somerset's cottage industries. Farming continued to flourish, however, and the Bath and West of England Society for the Encouragement of Agriculture, Arts, Manufactures and Commerce was founded in 1777 to improve farming methods. Despite this, 20 years later John Billingsley conducted a survey of the county's agriculture in 1795 and found that agricultural methods could still be improved. Coal mining was an important industry in north Somerset during the 18th and 19th centuries, and by 1800 it was prominent in Radstock. The Somerset Coalfield reached its peak production by the 1920s, but all the pits have now been closed, the last in 1973. Most of the surface buildings have been removed, and apart from a winding wheel outside Radstock Museum, little evidence of their former existence remains. Further west, the Brendon Hills were mined for iron ore in the late 19th century; this was taken by the West Somerset Mineral Railway to Watchet Harbour for shipment to the furnaces at Ebbw Vale.

In what year did coal mining begin in Somerset?