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.

Let me give you an example: 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.
The answer to this example can be: None
Here is why: 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.

OK. solve this:
proper question: How are the certain costs which are difficult to avoid shared? 
 disfluent question: What are or rather how are the certain costs which are difficult to avoid shared? 
 context: Firstly, certain costs are difficult to avoid and are shared by everyone, such as the costs of housing, pensions, education and health care. If the state does not provide these services, then for those on lower incomes, the costs must be borrowed and often those on lower incomes are those who are worse equipped to manage their finances. Secondly, aspirational consumption describes the process of middle income earners aspiring to achieve the standards of living enjoyed by their wealthier counterparts and one method of achieving this aspiration is by taking on debt. The result leads to even greater inequality and potential economic instability.
Answer:
by everyone