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.

Example Input: Passage: The National Incident Based Reporting System (NIBRS) crime statistics system aims to address limitations inherent in UCR data. The system is used by law enforcement agencies in the United States for collecting and reporting data on crimes. Local, state, and federal agencies generate NIBRS data from their records management systems. Data is collected on every incident and arrest in the Group A offense category. The Group A offenses are 46 specific crimes grouped in 22 offense categories. Specific facts about these offenses are gathered and reported in the NIBRS system. In addition to the Group A offenses, eleven Group B offenses are reported with only the arrest information. The NIBRS system is in greater detail than the summary-based UCR system. As of 2004, 5,271 law enforcement agencies submitted NIBRS data. That amount represents 20% of the United States population and 16% of the crime statistics data collected by the FBI.
Example Output: What system do Canadian law enforcement agencies use?

Example Input: Passage: For instance, a common use of a database system is to track information about users, their name, login information, various addresses and phone numbers. In the navigational approach all of this data would be placed in a single record, and unused items would simply not be placed in the database. In the relational approach, the data would be normalized into a user table, an address table and a phone number table (for instance). Records would be created in these optional tables only if the address or phone numbers were actually provided.
Example Output: How is a database system rarely used?

Example Input: Passage: The fortified city temporarily fell to the French invasion in 1672 (the Disaster Year); where the French invasion was only stopped west of Utrecht at the Old Hollandic Waterline. In 1674, only two years after the French left, the centre of Utrecht was struck by a tornado. The halt to building before construction of flying buttresses in the 15th century now proved to be the undoing of the central section of the cathedral of St Martin church which collapsed; creating the current Dom square between the tower and choir. In 1713, Utrecht hosted one of the first international peace negotiations when the Treaty of Utrecht settled the War of the Spanish Succession. Since 1723 Utrecht became the centre of the non-Roman Old Catholic Churches in the world.
Example Output:
Who did the city fall to in the 16th century?