TASK DEFINITION: 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.
PROBLEM: Passage: The noise-based speed is defined as the exposure that will lead to a given signal-to-noise ratio on individual pixels. Two ratios are used, the 40:1 ("excellent image quality") and the 10:1 ("acceptable image quality") ratio. These ratios have been subjectively determined based on a resolution of 70 pixels per cm (178 DPI) when viewed at 25 cm (9.8 inch) distance. The signal-to-noise ratio is defined as the standard deviation of a weighted average of the luminance and color of individual pixels. The noise-based speed is mostly determined by the properties of the sensor and somewhat affected by the noise in the electronic gain and AD converter.

SOLUTION: Which ratio was subjectively determined?

PROBLEM: Passage: In Ireland, private schools (Irish: scoil phríobháideach) are unusual because a certain number of teacher's salaries are paid by the State. If the school wishes to employ extra teachers they are paid for with school fees, which tend to be relatively low in Ireland compared to the rest of the world. There is, however, a limited element of state assessment of private schools, because of the requirement that the state ensure that children receive a certain minimum education; Irish private schools must still work towards the Junior Certificate and the Leaving Certificate, for example. Many private schools in Ireland also double as boarding schools. The average fee is around €5,000 annually for most schools, but some of these schools also provide boarding and the fees may then rise up to €25,000 per year. The fee-paying schools are usually run by a religious order, i.e., the Society of Jesus or Congregation of Christian Brothers, etc.

SOLUTION: What is the Irish term for school fees?

PROBLEM: Passage: After this, Huguenots (with estimates ranging from 200,000 to 1,000,000) fled to surrounding Protestant countries: England, the Netherlands, Switzerland, Norway, Denmark, and Prussia — whose Calvinist Great Elector Frederick William welcomed them to help rebuild his war-ravaged and underpopulated country. Following this exodus, Huguenots remained in large numbers in only one region of France: the rugged Cévennes region in the south. In the early 18th century, a regional group known as the Camisards who were Huguenots rioted against the Catholic Church in the region, burning churches and killing clergy. It took French troops years to hunt down and destroy all the bands of Camisards, between 1702 and 1709.

SOLUTION:
In what year did Frederick William of Prussia become the Great Elector?