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: There is no natural source for green food colorings which has been approved by the US Food and Drug Administration. Chlorophyll, the E numbers E140 and E141, is the most common green chemical found in nature, and only allowed in certain medicines and cosmetic materials. Quinoline Yellow (E104) is a commonly used coloring in the United Kingdom but is banned in Australia, Japan, Norway and the United States. Green S (E142) is prohibited in many countries, for it is known to cause hyperactivity, asthma, urticaria, and insomnia.

Output: Which two E numbers have been approved by the FDA?


Input: Consider Input: Passage: One philosophical school which has historically had a close relationship with process philosophy is American pragmatism. Whitehead himself thought highly of William James and John Dewey, and acknowledged his indebtedness to them in the preface to Process and Reality. Charles Hartshorne (along with Paul Weiss) edited the collected papers of Charles Sanders Peirce, one of the founders of pragmatism. Noted neopragmatist Richard Rorty was in turn a student of Hartshorne. Today, Nicholas Rescher is one example of a philosopher who advocates both process philosophy and pragmatism.

Output:  What pragmatists did Whitehead not acknowledge in the preface to "Process and Reality"?


Input: Consider Input: Passage: By 1975 the majority of local authorities in England and Wales had abandoned the 11-plus examination and moved to a comprehensive system. Over that 10-year period many secondary modern schools and grammar schools were amalgamated to form large neighbourhood comprehensives, whilst a number of new schools were built to accommodate a growing school population. By the mid-1970s the system had been almost fully implemented, with virtually no secondary modern schools remaining. Many grammar schools were either closed or changed to comprehensive status. Some local authorities, including Sandwell and Dudley in the West Midlands, changed all of its state secondary schools to comprehensive schools during the 1970s.


Output: By what year didn't the 11-plus exam mainly fall out of use?