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: Marvel earned a great deal of money and recognition during the comic book boom of the early 1990s, launching the successful 2099 line of comics set in the future (Spider-Man 2099, etc.) and the creatively daring though commercially unsuccessful Razorline imprint of superhero comics created by novelist and filmmaker Clive Barker. In 1990, Marvel began selling Marvel Universe Cards with trading card maker SkyBox International. These were collectible trading cards that featured the characters and events of the Marvel Universe. The 1990s saw the rise of variant covers, cover enhancements, swimsuit issues, and company-wide crossovers that affected the overall continuity of the fictional Marvel Universe
Output:
What series was set in the past?