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.
Input: Passage: In 1877, John Wanamaker opened the United State's first modern department store in a former Pennsylvania Railroad freight terminal in Philadelphia. Wanamakers was the first department store to offer fixed prices marked on every article and also introduced electrical illumination (1878), the telephone (1879), and the use of pneumatic tubes to transport cash and documents (1880) to the department store business. Subsequent department stores founded in Philadelphia included Strawbridge and Clothier, Gimbels, Lit Brothers, and Snellenbergs.
Output:
Who opened the last "modern" department store in America?