Use a disfluent question or a proper question and find the answer to the question based on the given context or return None if an answer can't be found. A disfluent question is a question that has some interruptions in it while framing. A proper question is the correct form of the question without any disfluency.

Example input: proper question: In what year did the U of C become one of 7 founding members of the Association of Chicago Universities?
disfluent question: In what year did Robert Harper or did the U of C become one of 7 founding members of the Association of Chicago Universities?
context: Founded by the American Baptist Education Society with a donation from oil magnate and wealthiest man in history John D. Rockefeller, the University of Chicago was incorporated in 1890; William Rainey Harper became the university's first president in 1891, and the first classes were held in 1892. Both Harper and future president Robert Maynard Hutchins advocated for Chicago's curriculum to be based upon theoretical and perennial issues rather than on applied sciences and commercial utility. With Harper's vision in mind, the University of Chicago also became one of the 14 founding members of the Association of American Universities, an international organization of leading research universities, in 1900.
Example output: None
Example explanation: The answer to the above question is not found from the context hence it is not answerable so the output is 'None' so it is a positive example.
Q: proper question: Which is less costly, formal, or informal imperialism?
disfluent question: Which is containing perceivable kinds of dominance no um which still less costly, formal, or informal imperialism?
context: The definition of imperialism has not been finalized for centuries and was confusedly seen to represent the policies of major powers, or simply, general-purpose aggressiveness. Further on, some writers[who?] used the term imperialism, in slightly more discriminating fashion, to mean all kinds of domination or control by a group of people over another. To clear out this confusion about the definition of imperialism one could speak of formal and informal imperialism, the first meaning physical control or full-fledged colonial rule while the second implied less direct rule though still containing perceivable kinds of dominance. Informal rule is generally less costly than taking over territories formally. This is because, with informal rule, the control is spread more subtly through technological superiority, enforcing land officials into large debts that cannot be repaid, ownership of private industries thus expanding the controlled area, or having countries agree to uneven trade agreements forcefully.
A:
None