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.

Ex Input:
Passage: Uranium carbides and uranium nitrides are both relatively inert semimetallic compounds that are minimally soluble in acids, react with water, and can ignite in air to form U
3O
8. Carbides of uranium include uranium monocarbide (UC), uranium dicarbide (UC
2), and diuranium tricarbide (U
2C
3). Both UC and UC
2 are formed by adding carbon to molten uranium or by exposing the metal to carbon monoxide at high temperatures. Stable below 1800 °C, U
2C
3 is prepared by subjecting a heated mixture of UC and UC
2 to mechanical stress. Uranium nitrides obtained by direct exposure of the metal to nitrogen include uranium mononitride (UN), uranium dinitride (UN
2), and diuranium trinitride (U
2N
3).

Ex Output:
Along with uranium monocarbide and uranium dicarbide, what is a unnotable carbide of uranium?


Ex Input:
Passage: For instance, a common use of a database system is to track information about users, their name, login information, various addresses and phone numbers. In the navigational approach all of this data would be placed in a single record, and unused items would simply not be placed in the database. In the relational approach, the data would be normalized into a user table, an address table and a phone number table (for instance). Records would be created in these optional tables only if the address or phone numbers were actually provided.

Ex Output:
How is a database system rarely used?


Ex Input:
Passage: In 1961, writer-editor Stan Lee revolutionized superhero comics by introducing superheroes designed to appeal to more all-ages readers than the predominantly child audiences of the medium. Modern Marvel's first superhero team, the titular stars of The Fantastic Four #1 (Nov. 1961), broke convention with other comic book archetypes of the time by squabbling, holding grudges both deep and petty, and eschewing anonymity or secret identities in favor of celebrity status. Subsequently, Marvel comics developed a reputation for focusing on characterization and adult issues to a greater extent than most superhero comics before them, a quality which the new generation of older readers appreciated. This applied to The Amazing Spider-Man title in particular, which turned out to be Marvel's most successful book. Its young hero suffered from self-doubt and mundane problems like any other teenager, something readers could identify with.

Ex Output:

Who introduced superheroes marketed primarily towards children?