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.

[EX Q]: Passage: The most precise timekeeping device of the ancient world was the water clock, or clepsydra, one of which was found in the tomb of Egyptian pharaoh Amenhotep I (1525–1504 BC). They could be used to measure the hours even at night, but required manual upkeep to replenish the flow of water. The Ancient Greeks and the people from Chaldea (southeastern Mesopotamia) regularly maintained timekeeping records as an essential part of their astronomical observations. Arab inventors and engineers in particular made improvements on the use of water clocks up to the Middle Ages. In the 11th century, Chinese inventors and engineers invented the first mechanical clocks driven by an escapement mechanism.
[EX A]: What device was invented by the ancient Greeks?

[EX 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.
[EX A]: What did YouTube launch in January 2008?

[EX Q]: Passage: Niels Bohr introduced the first quantized model of the atom in 1913, in an attempt to overcome a major shortcoming of Rutherford's classical model. In classical electrodynamics, a charge moving in a circle should radiate electromagnetic radiation. If that charge were to be an electron orbiting a nucleus, the radiation would cause it to lose energy and spiral down into the nucleus. Bohr solved this paradox with explicit reference to Planck's work: an electron in a Bohr atom could only have certain defined energies En
[EX A]:
Who introduced the last quantized model of the atom?