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: Even though some proofs of complexity-theoretic theorems regularly assume some concrete choice of input encoding, one tries to keep the discussion abstract enough to be independent of the choice of encoding. This can be achieved by ensuring that different representations can be transformed into each other efficiently.

Ex Output:
What can not be achieved by ensuring different representations can transformed into each other efficiently?


Ex Input:
Passage: The thalidomide tragedy resurrected Kefauver's bill to enhance drug regulation that had stalled in Congress, and the Kefauver-Harris Amendment became law on 10 October 1962. Manufacturers henceforth had to prove to FDA that their drugs were effective as well as safe before they could go on the US market. The FDA received authority to regulate advertising of prescription drugs and to establish good manufacturing practices. The law required that all drugs introduced between 1938 and 1962 had to be effective. An FDA - National Academy of Sciences collaborative study showed that nearly 40 percent of these products were not effective. A similarly comprehensive study of over-the-counter products began ten years later.

Ex Output:
When did the FDA Amendment become a law?


Ex Input:
Passage: In the 2015 US News & World Report America's Best Graduate Schools, the law school is ranked 18th nationally, out of over 180 law schools. In particular, its Clinical Education Program is currently ranked 4th in the nation. This year, the median score placed the average student in the 96th percentile of test takers. The law school offers a full-time day program, beginning in August, for the J.D. degree. The law school is located in a state-of-the-art building, Anheuser-Busch Hall (opened in 1997). The building combines traditional architecture, a five-story open-stacks library, an integration of indoor and outdoor spaces, and the latest wireless and other technologies. National Jurist ranked Washington University 4th among the "25 Most Wired Law Schools."

Ex Output:

In 2015 what graduate school was ranked best by US News & World Report?