This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) its answer is a continuous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage.

Ex Input:
With the defeat of Marshal Bazaine's Army of the Rhine at Gravelotte, the French were forced to retire to Metz, where they were besieged by over 150,000 Prussian troops of the First and Second Armies. Napoleon III and MacMahon formed the new French Army of Châlons, to march on to Metz to rescue Bazaine. Napoleon III personally led the army with Marshal MacMahon in attendance. The Army of Châlons marched northeast towards the Belgian border to avoid the Prussians before striking south to link up with Bazaine. The Prussians, under the command of Field Marshal Count Helmuth von Moltke, took advantage of this maneuver to catch the French in a pincer grip. He left the Prussian First and Second Armies besieging Metz, except three corps detached to form the Army of the Meuse under the Crown Prince of Saxony. With this army and the Prussian Third Army, Moltke marched northward and caught up with the French at Beaumont on 30 August. After a sharp fight in which they lost 5,000 men and 40 cannons, the French withdrew toward Sedan. Having reformed in the town, the Army of Châlons was immediately isolated by the converging Prussian armies. Napoleon III ordered the army to break out of the encirclement immediately. With MacMahon wounded on the previous day, General Auguste Ducrot took command of the French troops in the field.

Ex Output:
What factor forced the French to retreat to Metz?


Ex Input:
Mahayana Buddhism received significant theoretical grounding from Nagarjuna (perhaps c. 150–250 CE), arguably the most influential scholar within the Mahayana tradition. Nagarjuna's primary contribution to Buddhist philosophy was the systematic exposition of the concept of śūnyatā, or "emptiness", widely attested in the Prajñāpāramitā sutras that emerged in his era. The concept of emptiness brings together other key Buddhist doctrines, particularly anatta and dependent origination, to refute the metaphysics of Sarvastivada and Sautrantika (extinct non-Mahayana schools). For Nagarjuna, it is not merely sentient beings that are empty of ātman; all phenomena (dharmas) are without any svabhava (literally "own-nature" or "self-nature"), and thus without any underlying essence; they are "empty" of being independent; thus the heterodox theories of svabhava circulating at the time were refuted on the basis of the doctrines of early Buddhism. Nagarjuna's school of thought is known as the Mādhyamaka. Some of the writings attributed to Nagarjuna made explicit references to Mahayana texts, but his philosophy was argued within the parameters set out by the agamas. He may have arrived at his positions from a desire to achieve a consistent exegesis of the Buddha's doctrine as recorded in the Canon. In the eyes of Nagarjuna the Buddha was not merely a forerunner, but the very founder of the Mādhyamaka system.

Ex Output:
Nagarjuna's main contribution was the exposition of the concept of what?


Ex Input:
The final son of Abd al-Malik to become caliph was Hisham (724–43), whose long and eventful reign was above all marked by the curtailment of military expansion. Hisham established his court at Resafa in northern Syria, which was closer to the Byzantine border than Damascus, and resumed hostilities against the Byzantines, which had lapsed following the failure of the last siege of Constantinople. The new campaigns resulted in a number of successful raids into Anatolia, but also in a major defeat (the Battle of Akroinon), and did not lead to any significant territorial expansion.

Ex Output:

Who was the father of Hisham?