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.

Passage: The Wayback Machine is a digital archive of the World Wide Web and other information on the Internet created by the Internet Archive, a nonprofit organization, based in San Francisco, California, United States. It was set up by Brewster Kahle and Bruce Gilliat, and is maintained with content from Alexa Internet. The service enables users to see archived versions of web pages across time, which the archive calls a "three dimensional index."
Where does the information stored on the Internet Archive come from?

Passage: Samkhya school espouses dualism between consciousness and matter. It regards the universe as consisting of two realities; Puruṣa (consciousness) and prakriti (matter). Jiva (a living being) is that state in which puruṣa is bonded to prakriti in some form. This fusion, state the Samkhya scholars, led to the emergence of buddhi (awareness, intellect) and ahankara (individualized ego consciousness, “I-maker”). The universe is described by this school as one created by Purusa-Prakriti entities infused with various permutations and combinations of variously enumerated elements, senses, feelings, activity and mind.
What school rejects dualism?

Passage: San Diego's roadway system provides an extensive network of routes for travel by bicycle. The dry and mild climate of San Diego makes cycling a convenient and pleasant year-round option. At the same time, the city's hilly, canyon-like terrain and significantly long average trip distances—brought about by strict low-density zoning laws—somewhat restrict cycling for utilitarian purposes. Older and denser neighborhoods around the downtown tend to be utility cycling oriented. This is partly because of the grid street patterns now absent in newer developments farther from the urban core, where suburban style arterial roads are much more common. As a result, a vast majority of cycling-related activities are recreational. Testament to San Diego's cycling efforts, in 2006, San Diego was rated as the best city for cycling for U.S. cities with a population over 1 million.

In what year was San Diego rated as the country's worst densely populated city for cycling?