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: In 1872, Russian Alexander Lodygin invented an incandescent light bulb and obtained a Russian patent in 1874. He used as a burner two carbon rods of diminished section in a glass receiver, hermetically sealed, and filled with nitrogen, electrically arranged so that the current could be passed to the second carbon when the first had been consumed. Later he lived in the USA, changed his name to Alexander de Lodyguine and applied and obtained patents for incandescent lamps having chromium, iridium, rhodium, ruthenium, osmium, molybdenum and tungsten filaments, and a bulb using a molybdenum filament was demonstrated at the world fair of 1900 in Paris.
[A]: Who did not patent an incandescent light bulb in 1872?


[Q]: Passage: A TiVo service update in July 2008 allowed the system to search and play YouTube videos. In January 2009, YouTube launched "YouTube for TV", a version of the website tailored for set-top boxes and other TV-based media devices with web browsers, initially allowing its videos to be viewed on the PlayStation 3 and Wii video game consoles. In June 2009, YouTube XL was introduced, which has a simplified interface designed for viewing on a standard television screen. YouTube is also available as an app on Xbox Live. On November 15, 2012, Google launched an official app for the Wii, allowing users to watch YouTube videos from the Wii channel. An app is also available for Wii U and Nintendo 3DS, and videos can be viewed on the Wii U Internet Browser using HTML5. Google made YouTube available on the Roku player on December 17, 2013 and in October 2014, the Sony PlayStation 4.
[A]: What did YouTube launch in January 2008?


[Q]: Passage: With two-cylinder compounds used in railway work, the pistons are connected to the cranks as with a two-cylinder simple at 90° out of phase with each other (quartered). When the double expansion group is duplicated, producing a 4-cylinder compound, the individual pistons within the group are usually balanced at 180°, the groups being set at 90° to each other. In one case (the first type of Vauclain compound), the pistons worked in the same phase driving a common crosshead and crank, again set at 90° as for a two-cylinder engine. With the 3-cylinder compound arrangement, the LP cranks were either set at 90° with the HP one at 135° to the other two, or in some cases all three cranks were set at 120°.[citation needed]
[A]:
At what degree are the pistons of a two-cylinder compound connected to the pistons?