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: Oxygen was discovered independently by Carl Wilhelm Scheele, in Uppsala, in 1773 or earlier, and Joseph Priestley in Wiltshire, in 1774, but Priestley is often given priority because his work was published first. The name oxygen was coined in 1777 by Antoine Lavoisier, whose experiments with oxygen helped to discredit the then-popular phlogiston theory of combustion and corrosion. Its name derives from the Greek roots oxys, "acid", literally "sharp", referring to the sour taste of acids and - -genes, "producer", literally "begetter", because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition. Common uses of oxygen includes the production cycle of steel, plastics and textiles, brazing, welding and cutting of steels and other metals, rocket propellant, in oxygen therapy and life support systems in aircraft, submarines, spaceflight and diving.

Answer: When did Carl Priestly discover oxygen?

Question: Passage: During the 1950s and 1960s, FBI officials became increasingly concerned about the influence of civil rights leaders, whom they believed had communist ties or were unduly influenced by them. In 1956, for example, Hoover sent an open letter denouncing Dr. T.R.M. Howard, a civil rights leader, surgeon, and wealthy entrepreneur in Mississippi who had criticized FBI inaction in solving recent murders of George W. Lee, Emmett Till, and other blacks in the South. The FBI carried out controversial domestic surveillance in an operation it called the COINTELPRO, which was short for "COunter-INTELligence PROgram." It was to investigate and disrupt the activities of dissident political organizations within the United States, including both militant and non-violent organizations. Among its targets was the Southern Christian Leadership Conference, a leading civil rights organization with clergy leadership.

Answer: When did FBI officials become less concerned about Civil Rights?

Question: Passage: Provided is a universal Ku band LNB (9.75/10.600 GHz) which is fitted at the end of the dish and pointed at the correct satellite constellation; most digital receivers will receive the free to air channels. Some broadcasts are free-to-air and unencrypted, some are encrypted but do not require a monthly subscription (known as free-to-view), some are encrypted and require a monthly subscription, and some are pay-per-view services. To view the encrypted content a VideoGuard UK equipped receiver (all of which are dedicated to the Sky service, and cannot be used to decrypt other services) needs to be used. Unofficial CAMs are now available to view the service, although use of them breaks the user's contract with Sky and invalidates the user's rights to use the card.

Answer:
What do encrypted broadcasts never require?