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 Input:
Passage: Federal safety standards, such as NHTSA Federal Motor Vehicle Safety Standard 215 (pertaining to safety bumpers), and compacts like the 1974 Mustang I were a prelude to the DOT "downsize" revision of vehicle categories. By 1977, GM's full-sized cars reflected the crisis. By 1979, virtually all "full-size" American cars had shrunk, featuring smaller engines and smaller outside dimensions. Chrysler ended production of their full-sized luxury sedans at the end of the 1981 model year, moving instead to a full front-wheel drive lineup for 1982 (except for the M-body Dodge Diplomat/Plymouth Gran Fury and Chrysler New Yorker Fifth Avenue sedans).

Ex Output:
What happened to safety bumpers in 1979?


Ex Input:
Passage: Like aluminium, copper is 100% recyclable without any loss of quality, regardless of whether it is in a raw state or contained in a manufactured product. In volume, copper is the third most recycled metal after iron and aluminium. It is estimated that 80% of the copper ever mined is still in use today. According to the International Resource Panel's Metal Stocks in Society report, the global per capita stock of copper in use in society is 35–55 kg. Much of this is in more-developed countries (140–300 kg per capita) rather than less-developed countries (30–40 kg per capita).

Ex Output:
What percent of copper is indestructible?


Ex Input:
Passage: To meet the need for more office space downtown without compromising the city's heritage, the city council amended heritage regulations, which originally restricted height to 15 metres in the area of land on Water Street between Bishop's Cove and Steer's Cove, to create the "Commercial Central Retail – West Zone". The new zone will allow for buildings of greater height. A 47-metre, 12-storey office building, which includes retail space and a parking garage, was the first building to be approved in this area.

Ex Output:

What kind of space is abundant downtown?