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.

[Q]: Passage: CBC Television stations can be received in many United States communities along the Canadian border over-the-air and have a significant audience in those areas. Such a phenomenon can also take place within Great Lakes communities such as Ashtabula, Ohio, which received programming from the CBC's London, Ontario, transmitter, based upon prevailing atmospheric conditions over Lake Erie. As of September 2010 CBC shut down its analogue transmitter and decided not to replace it with a digital transmitter. As a result, there is now a giant hole in the coverage of CBC in South-Western Ontario. Both CBC - Toronto and CBC - Windsor are both over 100 miles from London, ON and out of range for even the largest antennas[citation needed].
[A]: What location in the United States has the highest viewership of CBC programming?


[Q]: Passage: Northwestern fielded its first intercollegiate football team in 1882, later becoming a founding member of the Big Ten Conference. In the 1870s and 1880s, Northwestern affiliated itself with already existing schools of law, medicine, and dentistry in Chicago. The Northwestern University School of Law is the oldest law school in Chicago. As the university increased in wealth and distinction, and enrollments grew, these professional schools were integrated with the undergraduate college in Evanston; the result was a modern research university combining professional, graduate, and undergraduate programs, which gave equal weight to teaching and research. The Association of American Universities invited Northwestern to become a member in 1917.
[A]:  What sports team did Northwestern field its first of in 1982?


[Q]: Passage: In 1906, precipitation hardening alloys were discovered by Alfred Wilm. Precipitation hardening alloys, such as certain alloys of aluminium, titanium, and copper, are heat-treatable alloys that soften when quenched (cooled quickly), and then harden over time. After quenching a ternary alloy of aluminium, copper, and magnesium, Wilm discovered that the alloy increased in hardness when left to age at room temperature. Although an explanation for the phenomenon was not provided until 1919, duralumin was one of the first "age hardening" alloys to be used, and was soon followed by many others. Because they often exhibit a combination of high strength and low weight, these alloys became widely used in many forms of industry, including the construction of modern aircraft.
[A]:
What is done to make precipitation hardening alloys hardened immediately?