Problem: Given the question: Question: "Which is better for bulk transmission if you want to avoid loss, AC or DC power?" Context: "There has, however, been interest among railroad operators in returning to DC use at higher voltages than previously used. At the same voltage, DC often has less loss than AC, and for this reason high-voltage direct current is already used on some bulk power transmission lines. DC avoids the electromagnetic radiation inherent with AC, and on a railway this also reduces interference with signalling and communications and mitigates hypothetical EMF risks. DC also avoids the power factor problems of AC. Of particular interest to railroading is that DC can supply constant power with a single ungrounded wire. Constant power with AC requires three-phase transmission with at least two ungrounded wires. Another important consideration is that mains-frequency 3-phase AC must be carefully planned to avoid unbalanced phase loads. Parts of the system are supplied from different phases on the assumption that the total loads of the 3 phases will even out. At the phase break points between regions supplied from different phases, long insulated supply breaks are required to avoid them being shorted by rolling stock using more than one pantograph at a time. A few railroads have tried 3-phase but its substantial complexity has made single-phase standard practice despite the interruption in power flow that occurs twice every cycle. An experimental 6 kV DC railway was built in the Soviet Union." Answer:
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The answer is:
DC

Problem: Given the question: Question: "Which happened first: World War II or the Northland Center Hudson's rebranding?" Context: "After World War II Hudson's realized that the limited parking space at its downtown skyscraper would increasingly be a problem for its customers. The solution in 1954 was to open the Northland Center in nearby Southfield, just beyond the city limits. It was the largest suburban shopping center in the world, and quickly became the main shopping destination for northern and western Detroit, and for much of the suburbs. By 1961 the downtown skyscraper accounted for only half of Hudson's sales; it closed in 1986. The Northland Center Hudson's, rebranded Macy's in 2006 following acquisition by Federated Department Stores, was closed along with the remaining stores in the center in March 2015 due to the mall's high storefront vacancy, decaying infrastructure, and financial mismanagement." Answer:
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The answer is:
World War II

Problem: Given the question: Question: "What was released during the 7th year of the 21st century?" Context: "Under the supervision of May and Taylor, numerous restoration projects have been under way involving Queen's lengthy audio and video catalogue. DVD releases of their 1986 Wembley concert (titled Live at Wembley Stadium), 1982 Milton Keynes concert (Queen on Fire Live at the Bowl), and two Greatest Video Hits (Volumes 1 and 2, spanning the 1970s and 1980s) have seen the band's music remixed into 5.1 and DTS surround sound. So far, only two of the band's albums, A Night at the Opera and The Game, have been fully remixed into high-resolution multichannel surround on DVD-Audio. A Night at the Opera was re-released with some revised 5.1 mixes and accompanying videos in 2005 for the 30th anniversary of the album's original release (CD+DVD-Video set). In 2007, a Blu-ray edition of Queen's previously released concerts, Queen Rock Montreal & Live Aid, was released, marking their first project in 1080p HD." Answer:
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The answer is:
a Blu-ray edition of Queen's previously released concerts, Queen Rock Montreal & Live Aid