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 Q]: Passage: Robert Guiscard, an other Norman adventurer previously elevated to the dignity of count of Apulia as the result of his military successes, ultimately drove the Byzantines out of southern Italy. Having obtained the consent of pope Gregory VII and acting as his vassal, Robert continued his campaign conquering the Balkan peninsula as a foothold for western feudal lords and the Catholic Church. After allying himself with Croatia and the Catholic cities of Dalmatia, in 1081 he led an army of 30,000 men in 300 ships landing on the southern shores of Albania, capturing Valona, Kanina, Jericho (Orikumi), and reaching Butrint after numerous pillages. They joined the fleet that had previously conquered Corfu and attacked Dyrrachium from land and sea, devastating everything along the way. Under these harsh circumstances, the locals accepted the call of emperor Alexius I Comnenus to join forces with the Byzantines against the Normans. The Albanian forces could not take part in the ensuing battle because it had started before their arrival. Immediately before the battle, the Venetian fleet had secured a victory in the coast surrounding the city. Forced to retreat, Alexius ceded the command to a high Albanian official named Comiscortes in the service of Byzantium. The city's garrison resisted until February 1082, when Dyrrachium was betrayed to the Normans by the Venetian and Amalfitan merchants who had settled there. The Normans were now free to penetrate into the hinterland; they took Ioannina and some minor cities in southwestern Macedonia and Thessaly before appearing at the gates of Thessalonica. Dissension among the high ranks coerced the Normans to retreat to Italy. They lost Dyrrachium, Valona, and Butrint in 1085, after the death of Robert.
[EX A]: Who ultimatly drove the Byzantines out of Europe?

[EX Q]: 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 A]: In the US, electric traction became more energy-efficient than what?

[EX Q]: Passage: Bradley was the apparent target of G. E. Moore's radical rejection of idealism. Moore claimed that Bradley did not understand the statement that something is real. We know for certain, through common sense and prephilosophical beliefs, that some things are real, whether they are objects of thought or not, according to Moore. The 1903 article The Refutation of Idealism is one of the first demonstrations of Moore's commitment to analysis. He examines each of the three terms in the Berkeleian aphorism esse est percipi, "to be is to be perceived", finding that it must mean that the object and the subject are necessarily connected so that "yellow" and "the sensation of yellow" are identical - "to be yellow" is "to be experienced as yellow". But it also seems there is a difference between "yellow" and "the sensation of yellow" and "that esse is held to be percipi, solely because what is experienced is held to be identical with the experience of it". Though far from a complete refutation, this was the first strong statement by analytic philosophy against its idealist predecessors, or at any rate against the type of idealism represented by Berkeley. This argument did not show that the GEM (in post–Stove vernacular, see below) is logically invalid.
[EX A]:
What did Bradley write?