Problem: Mandolin:

The transition from the mandolino to the mandolin began around 1744 with the designing of the metal-string mandolin by the Vinaccia family, 3 brass strings and one of gut, using friction tuning pegs on a fingerboard that sat "flush" with the sound table. The mandolin grew in popularity over the next 60 years, in the streets where it was used by young men courting and by street musicians, and in the concert hall. After the Napoleonic Wars of 1815, however, its popularity began to fall. The 19th century produced some prominent players, including Bartolomeo Bortolazzi of Venice and Pietro Vimercati. However, professional virtuosity was in decline, and the mandolin music changed as the mandolin became a folk instrument; "the large repertoire of notated instrumental music for the mandolino and the mandoline was completely forgotten". The export market for mandolins from Italy dried up around 1815, and when Carmine de Laurentiis wrote a mandolin method in 1874, the Music World magazine wrote that the mandolin was "out of date." Salvador Leonardi mentioned this decline in his 1921 book, Methode pour Banjoline ou Mandoline-Banjo, saying that the mandolin had been declining in popularity from previous times.

Who were two of the promiment players in the 19th century?
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A: Bartolomeo Bortolazzi of Venice and Pietro Vimercati

Problem: In the United States, 25 Hz, a once-common industrial power frequency is used on Amtrak's 25 Hz traction power system at 12 kV on the Northeast Corridor between Washington, D.C. and New York City and on the Keystone Corridor between Harrisburg, Pennsylvania and Philadelphia. SEPTA's 25 Hz traction power system uses the same 12 kV voltage on the catenary in Northeast Philadelphia. This allows for the trains to operate on both the Amtrak and SEPTA power systems. Apart from having an identical catenary voltage, the power distribution systems of Amtrak and SEPTA are very different. The Amtrak power distribution system has a 138 kV transmission network that provides power to substations which then transform the voltage to 12 kV to feed the catenary system. The SEPTA power distribution system uses a 2:1 ratio autotransformer system, with the catenary fed at 12 kV and a return feeder wire fed at 24 kV. The New York, New Haven and Hartford Railroad used an 11 kV system between New York City and New Haven, Connecticut which was converted to 12.5 kV 60 Hz in 1987.
What uses a 1:2 ratio autotransformer?
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Answer: unanswerable

Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
Currently, the largest professional wrestling company worldwide is the United States-based WWE, which bought out many smaller regional companies in the late 20th century, as well as its primary US competitors WCW and Extreme Championship Wrestling (ECW) in early 2001. Other prominent professional wrestling companies worldwide include the US-based Total Nonstop Action Wrestling (TNA) and Ring of Honor (ROH), Consejo Mundial de Lucha Libre (CMLL) and Asistencia Asesoria y Administracion (AAA) in Mexico, and the Japanese New Japan Pro Wrestling (NJPW), All Japan Pro Wrestling (AJPW), and Pro Wrestling Noah (NOAH) leagues.
What are some other major wrestling companies?
A: Total Nonstop Action Wrestling (TNA) and Ring of Honor (ROH), Consejo Mundial de Lucha Libre (CMLL) and Asistencia Asesoria y Administracion (AAA)

Context and question: But house was also being developed on Ibiza,[citation needed] although no house artists or labels were coming from this tiny island at the time. By the mid-1980s a distinct Balearic mix of house was discernible.[citation needed] Several clubs such as Amnesia with DJ Alfredo were playing a mix of rock, pop, disco and house. These clubs, fueled by their distinctive sound and Ecstasy, began to have an influence on the British scene. By late 1987, DJs such as Trevor Fung, Paul Oakenfold and Danny Rampling were bringing the Ibiza sound to UK clubs such as the Hacienda in Manchester, and in London clubs such as Shoom in Southwark, Heaven, Future and Spectrum.
what was a popular club in ibiza that started playing dance and house music?
Answer: Amnesia

Question: In 586 BCE King Nebuchadnezzar II of Babylon conquered Judah. According to the Hebrew Bible, he destroyed Solomon's Temple and exiled the Jews to Babylon. The defeat was also recorded by the Babylonians (see the Babylonian Chronicles). In 538 BCE, Cyrus the Great of Persia conquered Babylon and took over its empire. Cyrus issued a proclamation granting subjugated nations (including the people of Judah) religious freedom (for the original text, which corroborates the biblical narrative only in very broad terms, see the Cyrus Cylinder). According to the Hebrew Bible 50,000 Judeans, led by Zerubabel, returned to Judah and rebuilt the temple. A second group of 5,000, led by Ezra and Nehemiah, returned to Judah in 456 BCE although non-Jews wrote to Cyrus to try to prevent their return.
Is there an answer to this question: Who conquered Judah?

Answer: King Nebuchadnezzar II

In 1949, the city was chosen to be the seat of the Council of Europe with its European Court of Human Rights and European Pharmacopoeia. Since 1952, the European Parliament has met in Strasbourg, which was formally designated its official 'seat' at the Edinburgh meeting of the European Council of EU heads of state and government in December 1992. (This position was reconfirmed and given treaty status in the 1997 Treaty of Amsterdam). However, only the (four-day) plenary sessions of the Parliament are held in Strasbourg each month, with all other business being conducted in Brussels and Luxembourg. Those sessions take place in the Immeuble Louise Weiss, inaugurated in 1999, which houses the largest parliamentary assembly room in Europe and of any democratic institution in the world. Before that, the EP sessions had to take place in the main Council of Europe building, the Palace of Europe, whose unusual inner architecture had become a familiar sight to European TV audiences. In 1992, Strasbourg became the seat of the Franco-German TV channel and movie-production society Arte.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): In what year did nations start negotiating the Treaty of Amsterdam?
Ah, so..
unanswerable