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.
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Question: Passage: Machine vision systems often require bright and homogeneous illumination, so features of interest are easier to process. LEDs are often used for this purpose, and this is likely to remain one of their major uses until the price drops low enough to make signaling and illumination uses more widespread. Barcode scanners are the most common example of machine vision, and many low cost products use red LEDs instead of lasers. Optical computer mice are an example of LEDs in machine vision, as it is used to provide an even light source on the surface for the miniature camera within the mouse. LEDs constitute a nearly ideal light source for machine vision systems for several reasons:

Answer:  non-LEDs are often used for what type of systems?


Question: Passage: The FBI has maintained files on numerous people, including celebrities such as Elvis Presley, Frank Sinatra, John Denver, John Lennon, Jane Fonda, Groucho Marx, Charlie Chaplin, the band MC5, Lou Costello, Sonny Bono, Bob Dylan, Michael Jackson, and Mickey Mantle. The files were collected for various reasons. Some of the subjects were investigated for alleged ties to the Communist party (Charlie Chaplin and Groucho Marx), or in connection with antiwar activities during the Vietnam War (John Denver, John Lennon, and Jane Fonda). Numerous celebrity files concern threats or extortion attempts against them (Sonny Bono, John Denver, John Lennon, Elvis Presley, Michael Jackson, Mickey Mantle, Groucho Marx, and Frank Sinatra).

Answer: Who has the FBI never maintained a file on?


Question: Passage: John Evans, for whom Evanston is named, bought 379 acres (153 ha) of land along Lake Michigan in 1853, and Philo Judson developed plans for what would become the city of Evanston, Illinois. The first building, Old College, opened on November 5, 1855. To raise funds for its construction, Northwestern sold $100 "perpetual scholarships" entitling the purchaser and his heirs to free tuition. Another building, University Hall, was built in 1869 of the same Joliet limestone as the Chicago Water Tower, also built in 1869, one of the few buildings in the heart of Chicago to survive the Great Chicago Fire of 1871. In 1873 the Evanston College for Ladies merged with Northwestern, and Frances Willard, who later gained fame as a suffragette and as one of the founders of the Woman's Christian Temperance Union (WCTU), became the school's first dean of women. Willard Residential College (1938) is named in her honor. Northwestern admitted its first women students in 1869, and the first woman was graduated in 1874.

Answer:
 What was the name of the first building opened in 1955?