You will be given a definition of a task first, then some input of the task.
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: St. John's is the eastern terminus of the Trans-Canada Highway, one of the longest national highways in the world. The divided highway, also known as "Outer Ring Road" in the city, runs just outside the main part of the city, with exits to Pitts Memorial Drive, Topsail Road, Team Gushue Highway, Thorburn Road, Allandale Road, Portugal Cove Road and Torbay Road, providing relatively easy access to neighbourhoods served by those streets. Pitts Memorial Drive runs from Conception Bay South, through the city of Mount Pearl and into downtown St. John's, with interchanges for Goulds, Water Street and Hamilton Avenue-New Gower Street.
Output:
What is the longest national highway in the world?