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: Code points in the range U+D800–U+DBFF (1,024 code points) are known as high-surrogate code points, and code points in the range U+DC00–U+DFFF (1,024 code points) are known as low-surrogate code points. A high-surrogate code point (also known as a leading surrogate) followed by a low-surrogate code point (also known as a trailing surrogate) together form a surrogate pair used in UTF-16 to represent 1,048,576 code points outside BMP. High and low surrogate code points are not valid by themselves. Thus the range of code points that are available for use as characters is U+0000–U+D7FF and U+E000–U+10FFFF (1,112,064 code points). The value of these code points (i.e., excluding surrogates) is sometimes referred to as the character's scalar value.

SOLUTION: What is a low-surrogate followed by a high-surrogate called?

PROBLEM: Passage: Spielberg won the Academy Award for Best Director for Schindler's List (1993) and Saving Private Ryan (1998). Three of Spielberg's films—Jaws (1975), E.T. the Extra-Terrestrial (1982), and Jurassic Park (1993)—achieved box office records, originated and came to epitomize the blockbuster film. The unadjusted gross of all Spielberg-directed films exceeds $9 billion worldwide, making him the highest-grossing director in history. His personal net worth is estimated to be more than $3 billion. He has been associated with composer John Williams since 1974, who composed music for all save five of Spielberg's feature films.

SOLUTION: How much have all Spielberg-directed films combined earned in adjusted gross?

PROBLEM: Passage: Most of the Huguenot congregations (or individuals) in North America eventually affiliated with other Protestant denominations with more numerous members. The Huguenots adapted quickly and often married outside their immediate French communities, which led to their assimilation. Their descendants in many families continued to use French first names and surnames for their children well into the nineteenth century. Assimilated, the French made numerous contributions to United States economic life, especially as merchants and artisans in the late Colonial and early Federal periods. For example, E.I. du Pont, a former student of Lavoisier, established the Eleutherian gunpowder mills.

SOLUTION:
In what century was Eleutherian gunpowder mills founded?