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: While its fellow Canadian broadcasters converted most of their transmitters to digital by the Canadian digital television transition deadline of August 31, 2011, CBC converted only about half of the analogue transmitters in mandatory areas to digital (15 of 28 markets with CBC Television stations, and 14 of 28 markets with Television de Radio-Canada stations). Due to financial difficulties reported by the corporation, the corporation published digital transition plans for none of its analogue retransmitters in mandatory markets to be converted to digital by the deadline. Under this plan, communities that receive analogue signals by rebroadcast transmitters in mandatory markets would lose their over-the-air signals as of the deadline. Rebroadcast transmitters account for 23 of the 48 CBC and Radio-Canada transmitters in mandatory markets. Mandatory markets losing both CBC and Radio-Canada over-the-air signals include London, Ontario (metropolitan area population 457,000) and Saskatoon, Saskatchewan (metro area population 257,000). In both of those markets, the corporation's television transmitters are the only ones that were not planned to be converted to digital by the deadline.
[A]: The CBC petitioned to change what original deadline for converting transmission from digital to analog?

[Q]: Passage: A few glaciers have periods of very rapid advancement called surges. These glaciers exhibit normal movement until suddenly they accelerate, then return to their previous state. During these surges, the glacier may reach velocities far greater than normal speed. These surges may be caused by failure of the underlying bedrock, the pooling of meltwater at the base of the glacier perhaps delivered from a supraglacial lake or the simple accumulation of mass beyond a critical "tipping point". Temporary rates up to 90 m (300 ft) per day have occurred when increased temperature or overlying pressure caused bottom ice to melt and water to accumulate beneath a glacier.
[A]: What is the term for a gradual increase in a glaciers speed?

[Q]: Passage: Linking the information back together is the key to this system. In the relational model, some bit of information was used as a "key", uniquely defining a particular record. When information was being collected about a user, information stored in the optional tables would be found by searching for this key. For instance, if the login name of a user is unique, addresses and phone numbers for that user would be recorded with the login name as its key. This simple "re-linking" of related data back into a single collection is something that traditional computer languages are not designed for.
[A]:
How is information hidden in a relational model?