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: In the former Soviet Union, electric traction eventually became somewhat more energy-efficient than diesel. Partly due to inefficient generation of electricity in the USSR (only 20.8% thermal efficiency in 1950 vs. 36.2% in 1975), in 1950 diesel traction was about twice as energy efficient as electric traction (in terms of net tonne-km of freight per kg of fuel). But as efficiency of electricity generation (and thus of electric traction) improved, by about 1965 electric railways became more efficient than diesel. After the mid 1970s electrics used about 25% less fuel per ton-km. However diesels were mainly used on single track lines with a fair amount of traffic  so that the lower fuel consumption of electrics may be in part due to better operating conditions on electrified lines (such as double tracking) rather than inherent energy efficiency. Nevertheless, the cost of diesel fuel was about 1.5 times more (per unit of heat energy content) than that of the fuel used in electric power plants (that generated electricity), thus making electric railways even more energy-cost effective.

Ex Output:
In the US, electric traction became more energy-efficient than what?


Ex Input:
Passage: Heresy is any provocative belief or theory that is strongly at variance with established beliefs or customs. A heretic is a proponent of such claims or beliefs. Heresy is distinct from both apostasy, which is the explicit renunciation of one's religion, principles or cause, and blasphemy, which is an impious utterance or action concerning God or sacred things.

Ex Output:
What is belief in a strongly held custom?


Ex Input:
Passage: According to the 2010 Census, whites made up 51% of Houston's population; 26% of the total population were non-Hispanic whites. Blacks or African Americans made up 25% of Houston's population. American Indians made up 0.7% of the population. Asians made up 6% (1.7% Vietnamese, 1.3% Chinese, 1.3% Indian, 0.9% Pakistani, 0.4% Filipino, 0.3% Korean, 0.1% Japanese), while Pacific Islanders made up 0.1%. Individuals from some other race made up 15.2% of the city's population, of which 0.2% were non-Hispanic. Individuals from two or more races made up 3.3% of the city. At the 2000 Census, there were 1,953,631 people and the population density was 3,371.7 people per square mile (1,301.8/km²). The racial makeup of the city was 49.3% White, 25.3% African American, 5.3% Asian, 0.7% American Indian, 0.1% Pacific Islander, 16.5% from some other race, and 3.1% from two or more races. In addition, Hispanics made up 37.4% of Houston's population while non-Hispanic whites made up 30.8%, down from 62.4% in 1970.

Ex Output:

How much of Texas's population is white?