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: Basic sanitation techniques can have a profound effect on the transmission of diarrheal disease. The implementation of hand washing using soap and water, for example, has been experimentally shown to reduce the incidence of disease by approximately 42–48%. Hand washing in developing countries, however, is compromised by poverty as acknowledged by the CDC: "Handwashing is integral to disease prevention in all parts of the world; however, access to soap and water is limited in a number of less developed countries. This lack of access is one of many challenges to proper hygiene in less developed countries." Solutions to this barrier require the implementation of educational programs that encourage sanitary behaviours.

Answer: What has a profound effect in developed countries?


Question: Passage: Paleoclimatologists measure the ratio of oxygen-18 and oxygen-16 in the shells and skeletons of marine organisms to determine what the climate was like millions of years ago (see oxygen isotope ratio cycle). Seawater molecules that contain the lighter isotope, oxygen-16, evaporate at a slightly faster rate than water molecules containing the 12% heavier oxygen-18; this disparity increases at lower temperatures. During periods of lower global temperatures, snow and rain from that evaporated water tends to be higher in oxygen-16, and the seawater left behind tends to be higher in oxygen-18. Marine organisms then incorporate more oxygen-18 into their skeletons and shells than they would in a warmer climate. Paleoclimatologists also directly measure this ratio in the water molecules of ice core samples that are up to several hundreds of thousands of years old.

Answer: Who measures oxygen-18 and oxygen-16 in skeletons of all organisms?


Question: Passage: Towns such as Castle Cary and Frome grew around the medieval weaving industry. Street developed as a centre for the production of woollen slippers and, later, boots and shoes, with C. & J. Clark establishing its headquarters in the town. C&J Clark's shoes are no longer manufactured there as the work was transferred to lower-wage areas, such as China and Asia. Instead, in 1993, redundant factory buildings were converted to form Clarks Village, the first purpose-built factory outlet in the UK. C&J Clark also had shoe factories, at one time at Bridgwater, Minehead, Westfield and Weston super Mare to provide employment outside the main summer tourist season, but those satellite sites were closed in the late 1980s, before the main site at Street. Dr. Martens shoes were also made in Somerset, by the Northampton-based R. Griggs Group, using redundant skilled shoemakers from C&J Clark; that work has also been transferred to Asia.

Answer:
When did C.&J. Clark shut down operations in Somerset?