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.

Passage: Red hair varies from a deep burgundy through burnt orange to bright copper. It is characterized by high levels of the reddish pigment pheomelanin (which also accounts for the red color of the lips) and relatively low levels of the dark pigment eumelanin. The term redhead (originally redd hede) has been in use since at least 1510. Cultural reactions have varied from ridicule to admiration; many common stereotypes exist regarding redheads and they are often portrayed as fiery-tempered. (See red hair).
How does copper hair vary?

Passage: On March 31, 2010, the YouTube website launched a new design, with the aim of simplifying the interface and increasing the time users spend on the site. Google product manager Shiva Rajaraman commented: "We really felt like we needed to step back and remove the clutter." In May 2010, it was reported that YouTube was serving more than two billion videos a day, which it described as "nearly double the prime-time audience of all three major US television networks combined". In May 2011, YouTube reported in its company blog that the site was receiving more than three billion views per day. In January 2012, YouTube stated that the figure had increased to four billion videos streamed per day.
What happened on March 30 2010?

Passage: Pfizer, once the city's second largest employer, operated a large pharmaceutical research facility on the northeast side of Ann Arbor. On 22 January 2007, Pfizer announced it would close operations in Ann Arbor by the end of 2008. The facility was previously operated by Warner-Lambert and, before that, Parke-Davis. In December 2008, the University of Michigan Board of Regents approved the purchase of the facilities, and the university anticipates hiring 2,000 researchers and staff during the next 10 years. The city is the home of other research and engineering centers, including those of Lotus Engineering, General Dynamics and the National Oceanic and Atmospheric Administration (NOAA). Other research centers sited in the city are the United States Environmental Protection Agency's National Vehicle and Fuel Emissions Laboratory and the Toyota Technical Center. The city is also home to National Sanitation Foundation International (NSF International), the nonprofit non-governmental organization that develops generally accepted standards for a variety of public health related industries and subject areas.

What pharmaceutical company was Ann Arbor's largest employer?