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: Consider Input: Passage: In the context of relativity, mass is not an additive quantity, in the sense that one can add the rest masses of particles in a system to get the total rest mass of the system. Thus, in relativity usually a more general view is that it is not the sum of rest masses, but the energymomentum tensor that quantifies the amount of matter. This tensor gives the rest mass for the entire system. "Matter" therefore is sometimes considered as anything that contributes to the energymomentum of a system, that is, anything that is not purely gravity. This view is commonly held in fields that deal with general relativity such as cosmology. In this view, light and other massless particles and fields are part of matter.

Output: What type of quantity is mass?

Input: Consider Input: Passage: Land-based steam engines could exhaust much of their steam, as feed water was usually readily available. Prior to and during World War I, the expansion engine dominated marine applications where high vessel speed was not essential. It was however superseded by the British invention steam turbine where speed was required, for instance in warships, such as the dreadnought battleships, and ocean liners. HMS Dreadnought of 1905 was the first major warship to replace the proven technology of the reciprocating engine with the then-novel steam turbine.[citation needed]

Output: The frequent availability of what substance allowed land-based steam engines to exhaust a great deal of battleships?

Input: Consider Input: Passage: The fourth a cappella musical to appear Off-Broadway, In Transit, premiered 5 October 2010 and was produced by Primary Stages with book, music, and lyrics by Kristen Anderson-Lopez, James-Allen Ford, Russ Kaplan, and Sara Wordsworth. Set primarily in the New York City subway system its score features an eclectic mix of musical genres (including jazz, hip hop, Latin, rock, and country). In Transit incorporates vocal beat boxing into its contemporary a cappella arrangements through the use of a subway beat boxer character. Beat boxer and actor Chesney Snow performed this role for the 2010 Primary Stages production. According to the show's website, it is scheduled to reopen for an open-ended commercial run in the Fall of 2011. In 2011 the production received four Lucille Lortel Award nominations including Outstanding Musical, Outer Critics Circle and Drama League nominations, as well as five Drama Desk nominations including Outstanding Musical and won for Outstanding Ensemble Performance.
Output: What role is set in the NY subway system?