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.

Input: Consider Input: Passage: Because of their long life, fast switching times, and their ability to be seen in broad daylight due to their high output and focus, LEDs have been used in brake lights for cars' high-mounted brake lights, trucks, and buses, and in turn signals for some time, but many vehicles now use LEDs for their rear light clusters. The use in brakes improves safety, due to a great reduction in the time needed to light fully, or faster rise time, up to 0.5 second faster[citation needed] than an incandescent bulb. This gives drivers behind more time to react. In a dual intensity circuit (rear markers and brakes) if the LEDs are not pulsed at a fast enough frequency, they can create a phantom array, where ghost images of the LED will appear if the eyes quickly scan across the array. White LED headlamps are starting to be used. Using LEDs has styling advantages because LEDs can form much thinner lights than incandescent lamps with parabolic reflectors.

Output: Why are non-LED lights sought after for various applications?

Input: Consider Input: Passage: The centrality of the "separation" concept to the Religion Clauses of the Constitution was made explicit in Everson v. Board of Education, 330 U.S. 1 (1947), a case dealing with a New Jersey law that allowed government funds to pay for transportation of students to both public and Catholic schools. This was the first case in which the court applied the Establishment Clause to the laws of a state, having interpreted the due process clause of the Fourteenth Amendment as applying the Bill of Rights to the states as well as the federal legislature. Citing Jefferson, the court concluded that "The First Amendment has erected a wall between church and state. That wall must be kept high and impregnable. We could not approve the slightest breach."

Output: When was the centrality of the "separation" concept to the Religion Clauses of the Constitution not made explicit?

Input: Consider Input: Passage: The Latin phrase on Northwestern's seal, Quaecumque sunt vera (Whatsoever things are true) is drawn from the Epistle of Paul to the Philippians 4:8, while the Greek phrase inscribed on the pages of an open book is taken from the Gospel of John 1:14: (The Word full of grace and truth). Purple became Northwestern's official color in 1892, replacing black and gold after a university committee concluded that too many other universities had used these colors. Today, Northwestern's official color is purple, although white is something of an official color as well, being mentioned in both the university's earliest song, Alma Mater (1907) ("Hail to purple, hail to white") and in many university guidelines.
Output: What has been Northwestern's official color since 1822?