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: What was the population density in 1970?
disfluent question: What racial group no What was the population density in 1970?
context: The 2010 United States Census reported that Fresno had a population of 494,665. The population density was 4,404.5 people per square mile (1,700.6/km). The racial makeup of Fresno was 245,306 (49.6%) White, 40,960 (8.3%) African American, 8,525 (1.7%) Native American, 62,528 (12.6%) Asian (3.6% Hmong, 1.7% Indian, 1.2% Filipino, 1.2% Laotian, 1.0% Thai, 0.8% Cambodian, 0.7% Chinese, 0.5% Japanese, 0.4% Vietnamese, 0.2% Korean), 849 (0.2%) Pacific Islander, 111,984 (22.6%) from other races, and 24,513 (5.0%) from two or more races. Hispanic or Latino of any race were 232,055 persons (46.9%). Among the Hispanic population, 42.7% of the total population are Mexican, 0.4% Salvadoran, and 0.4% Puerto Rican. Non-Hispanic Whites were 30.0% of the population in 2010, down from 72.6% in 1970.
Answer:
None