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: When Estonia was invaded and occupied by the Soviet Union in World War II, the status of the Estonian language changed to the first of two official languages (Russian being the other one). As with Latvia many immigrants entered Estonia under Soviet encouragement. In the second half of the 1970s, the pressure of bilingualism (for Estonians) intensified, resulting in widespread knowledge of Russian throughout the country. The Russian language was termed as 'the language of friendship of nations' and was taught to Estonian children, sometimes as early as in kindergarten. Although teaching Estonian to non-Estonians in schools was compulsory, in practice learning the language was often considered unnecessary.
What country did not occupy Estonia?

Passage: Like much of the south Atlantic region of the United States, Jacksonville has a humid subtropical climate (Koppen Cfa), with mild weather during winters and hot and humid weather during summers. Seasonal rainfall is concentrated in the warmest months from May through September, while the driest months are from November through April. Due to Jacksonville's low latitude and coastal location, the city sees very little cold weather, and winters are typically mild and sunny. Summers can be hot and wet, and summer thunderstorms with torrential but brief downpours are common.
Was city has a tropical climate?

Passage: In 1996, Marvel had some of its titles participate in "Heroes Reborn", a crossover that allowed Marvel to relaunch some of its flagship characters such as the Avengers and the Fantastic Four, and outsource them to the studios of two of the former Marvel artists turned Image Comics founders, Jim Lee and Rob Liefeld. The relaunched titles, which saw the characters transported to a parallel universe with a history distinct from the mainstream Marvel Universe, were a solid success amidst a generally struggling industry, but Marvel discontinued the experiment after a one-year run and returned the characters to the Marvel Universe proper. In 1998, the company launched the imprint Marvel Knights, taking place within Marvel continuity; helmed by soon-to-become editor-in-chief Joe Quesada, it featured tough, gritty stories showcasing such characters as the Inhumans, Black Panther and Daredevil.
Who created the Avengers?