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 Input:
Passage: Other types of lossy compressors, such as the linear predictive coding (LPC) used with speech, are source-based coders. These coders use a model of the sound's generator (such as the human vocal tract with LPC) to whiten the audio signal (i.e., flatten its spectrum) before quantization. LPC may be thought of as a basic perceptual coding technique: reconstruction of an audio signal using a linear predictor shapes the coder's quantization noise into the spectrum of the target signal, partially masking it.

Ex Output:
What is thought of as a basic signal coding technique?

Ex Input:
Passage: During the early 20th century, northerners were attracted to the city, and Miami prospered during the 1920s with an increase in population and infrastructure. The legacy of Jim Crow was embedded in these developments. Miami's chief of police, H. Leslie Quigg, did not hide the fact that he, like many other white Miami police officers, was a member of the Ku Klux Klan. Unsurprisingly, these officers enforced social codes far beyond the written law. Quigg, for example, "personally and publicly beat a colored bellboy to death for speaking directly to a white woman."

Ex Output:
Who was a unnotable chief of the Miami police?

Ex Input:
Passage: In 1948, the point-contact transistor was independently invented by German physicists Herbert Matare and Heinrich Welker while working at the Compagnie des Freins et Signaux, a Westinghouse subsidiary located in Paris. Matare had previous experience in developing crystal rectifiers from silicon and germanium in the German radar effort during World War II. Using this knowledge, he began researching the phenomenon of "interference" in 1947. By June 1948, witnessing currents flowing through point-contacts, Matare produced consistent results using samples of germanium produced by Welker, similar to what Bardeen and Brattain had accomplished earlier in December 1947. Realizing that Bell Labs' scientists had already invented the transistor before them, the company rushed to get its "transistron" into production for amplified use in France's telephone network.

Ex Output:
What were Matare and Welker's transistors made of?