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: This may be managed directly on an individual basis, or by the assignment of individuals and privileges to groups, or (in the most elaborate models) through the assignment of individuals and groups to roles which are then granted entitlements. Data security prevents unauthorized users from viewing or updating the database. Using passwords, users are allowed access to the entire database or subsets of it called "subschemas". For example, an employee database can contain all the data about an individual employee, but one group of users may be authorized to view only payroll data, while others are allowed access to only work history and medical data. If the DBMS provides a way to interactively enter and update the database, as well as interrogate it, this capability allows for managing personal databases.
[A]: What does data security support?


[Q]: Passage: The logical format of an audio CD (officially Compact Disc Digital Audio or CD-DA) is described in a document produced in 1980 by the format's joint creators, Sony and Philips. The document is known colloquially as the Red Book CD-DA after the colour of its cover. The format is a two-channel 16-bit PCM encoding at a 44.1 kHz sampling rate per channel. Four-channel sound was to be an allowable option within the Red Book format, but has never been implemented. Monaural audio has no existing standard on a Red Book CD; thus, mono source material is usually presented as two identical channels in a standard Red Book stereo track (i.e., mirrored mono); an MP3 CD, however, can have audio file formats with mono sound.
[A]: What was the sampling rate for the four-channel sound?


[Q]: Passage: The first railways in Thuringia had been built in the 1840s and the network of main lines was finished around 1880. By 1920, many branch lines had been built, giving Thuringia one of the densest rail networks in the world before World War II with about 2,500 km of track. Between 1950 and 2000 most of the branch lines were abandoned, reducing Thuringia's network by half compared to 1940. On the other hand, most of the main lines were refurbished after 1990, resulting in improved speed of travel. The most important railway lines at present are the Thuringian Railway, connecting Halle and Leipzig via Weimar, Erfurt, Gotha and Eisenach with Frankfurt and Kassel and the Saal Railway from Halle/Leipzig via Jena and Saalfeld to Nuremberg. The former has an hourly ICE/IC service from Dresden to Frankfurt while the latter is served hourly by ICE trains from Berlin to Munich. In 2017, a new high speed line will be opened, diverting long-distance services from these mid-19th century lines. Both ICE routes will then use the Erfurt–Leipzig/Halle high-speed railway, and the Berlin-Munich route will continue via the Nuremberg–Erfurt high-speed railway. Only the segment west of Erfurt of the Frankfurt-Dresden line will continue to be used by ICE trains after 2017, with an increased line speed of 200 km/h (currently 160 km/h). Erfurt's central station, which was completely rebuilt for this purpose in the 2000s (decade), will be the new connection between both ICE lines. The most important regional railway lines in Thuringia are the Neudietendorf–Ritschenhausen railway from Erfurt to Würzburg and Meiningen, the Weimar–Gera railway from Erfurt to Chemnitz, the Sangerhausen–Erfurt railway from Erfurt to Magdeburg, the Gotha–Leinefelde railway from Erfurt to Göttingen, the Halle–Kassel railway from Halle via Nordhausen to Kassel and the Leipzig–Hof railway from Leipzig via Altenburg to Zwickau and Hof. Most regional and local lines have hourly service, but some run only every other hour.
[A]:
When was Thuringia's worst railway built?