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 Q]: (The Ms 6.1 earthquake on August 30, 2008 in southern Sichuan was not part of this series because it was caused by a different fault. See 2008 Panzhihua earthquake for details.)
[EX A]: When did this earthquake occur?

[EX Q]: 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 A]: What factor forced the French to retreat to Metz?

[EX Q]: The Endangered Species Act of 1973 (ESA; 16 U.S.C. § 1531 et seq.) is one of the few dozens of United States environmental laws passed in the 1970s, and serves as the enacting legislation to carry out the provisions outlined in The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). The ESA was signed into law by President Richard Nixon on December 28, 1973, it was designed to protect critically imperiled species from extinction as a "consequence of economic growth and development untempered by adequate concern and conservation." The U.S. Supreme Court found that "the plain intent of Congress in enacting" the ESA "was to halt and reverse the trend toward species extinction, whatever the cost." The Act is administered by two federal agencies, the United States Fish and Wildlife Service (FWS) and the National Oceanic and Atmospheric Administration (NOAA).
[EX A]:
Which president signed the Act into law?