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: Tourism is a major industry owing to the city's climate, its beaches, and numerous tourist attractions such as Balboa Park, Belmont amusement park, San Diego Zoo, San Diego Zoo Safari Park, and SeaWorld San Diego. San Diego's Spanish and Mexican heritage is reflected in the many historic sites across the city, such as Mission San Diego de Alcala and Old Town San Diego State Historic Park. Also, the local craft brewing industry attracts an increasing number of visitors for "beer tours" and the annual San Diego Beer Week in November; San Diego has been called "America's Craft Beer Capital."

SOLUTION: What type of tours attract a large number of visitors to San Francisco?

PROBLEM: Passage: In the CFL, if the game is tied at the end of regulation play, then each team is given an equal number of chances to break the tie. A coin toss is held to determine which team will take possession first; the first team scrimmages the ball at the opponent's 35-yard line and advances through a series of downs until it scores or loses possession. If the team scores a touchdown, starting with the 2010 season, it is required to attempt a 2-point conversion. The other team then scrimmages the ball at the same 35-yard line and has the same opportunity to score. After the teams have completed their possessions, if one team is ahead, then it is declared the winner; otherwise, the two teams each get another chance to score, scrimmaging from the other 35-yard line. After this second round, if there is still no winner, during the regular season the game ends as a tie. In a playoff or championship game, the teams continue to attempt to score from alternating 35-yard lines, until one team is leading after both have had an equal number of possessions.

SOLUTION: After teams have completed their 2 point conversions, who is declared the winner?

PROBLEM: Passage: The Reinvent the Toilet Challenge is a long-term research and development effort to develop a hygienic, stand-alone toilet. This challenge is being complemented by another investment program to develop new technologies for improved pit latrine emptying (called by the foundation the "Omni-Ingestor") and fecal sludge processing (called "Omni-Processor"). The aim of the "Omni Processor" is to convert excreta (for example fecal sludge) into beneficial products such as energy and soil nutrients with the potential to develop local business and revenue.

SOLUTION:
What does Reinvent the Toilet Challenge convert into beneficial products?