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: BSkyB utilises the VideoGuard pay-TV scrambling system owned by NDS, a Cisco Systems company. There are tight controls over use of VideoGuard decoders; they are not available as stand-alone DVB CAMs (conditional-access modules). BSkyB has design authority over all digital satellite receivers capable of receiving their service. The receivers, though designed and built by different manufacturers, must conform to the same user interface look-and-feel as all the others. This extends to the Personal video recorder (PVR) offering (branded Sky+).

SOLUTION: What is the name of the TV scrambling system BSkyB couldn't use?

PROBLEM: Passage: Groups share a fundamental kinship with the notion of symmetry. For example, a symmetry group encodes symmetry features of a geometrical object: the group consists of the set of transformations that leave the object unchanged and the operation of combining two such transformations by performing one after the other. Lie groups are the symmetry groups used in the Standard Model of particle physics; Point groups are used to help understand symmetry phenomena in molecular chemistry; and Poincaré groups can express the physical symmetry underlying special relativity.

SOLUTION: What encodes a symmetry group?

PROBLEM: Passage: Like most other regions of central and southern Germany, Thuringia has a significant industrial sector reaching back to the mid-19th-century industrialisation. The economic transition after the German reunification in 1990 led to the closure of most large-scale factories and companies, leaving small and medium-sized ones to dominate the manufacturing sector. Well-known industrial centres are Jena (a world centre for optical instruments with companies like Carl Zeiss, Schott and Jenoptik) and Eisenach, where BMW started its car production in the 1920s and an Opel factory is based today. The most important industrial branches today are engineering and metalworking, vehicle production and food industries. Especially the small and mid-sized towns in central and southwestern Thuringia (e.g. Arnstadt, Schmalkalden and Ohrdruf) are highly industrialised, whereas there are fewer industrial companies in the northern and eastern parts of the Land. Traditional industries like production of glass, porcelain and toys collapsed during the economic crises between 1930 and 1990.

SOLUTION:
When was Thuringia's industrial sector eliminated?