Question: Which vessel of the British Cunard Line was the subject of a Philip Plisson photo collection? 
Context: The Ocean Steam Navigation Company (OSNC or Bremen Line) was a shipping company founded in 1847 in New York City by Edward Mills.  It was the first company to be awarded a contract by the US government for the oceanic transportation of mail.  In addition to the US contract, the company was partially subsidized by the Prussian government with the intention of increasing trade with the US out of the port of Bremen, hence the name Bremen Line.  The line began operations in June 1847 with the steamship "Washington", which completed her first eastbound voyage on June 15 and was joined by a sister ship, "Hermann".  Both vessels were slower than those operated by the Cunard Line, and the government revoked its contract with Oceanic by the end of 1847; it was later awarded to the Collins Line. "Washington" and "Hermann" both suffered mechanical difficulties, and Mills parted ways acrimoniously with the company—after giving control to investors but staying on as a manager, he tried to begin a competing line and was then fired from Oceanic.  Both the company's vessels rebuilt with improved propulsion systems in the early 1850s, but they remained slower than the competition.  After a brief upturn in business in 1855 when Cunard ships were chartered by the British government to serve in the Crimean War, competition returned to the North Atlantic the following year, as Cunard resumed service and German companies Hamburg America Line and Norddeutscher Lloyd began transatlantic crossings from German ports.  In July 1857, after losing its remaining US mail contract for traffic to Germany, Oceanic ceased operations. Cunard White Star Line, Ltd., was a British shipping line which existed between 1934 and 1949, It was created as an operating company to control the joint shipping assets of the Cunard Line and the White Star Line after both companies experienced financial difficulties during the Great Depression.  Cunard White Star controlled a total of twenty-five large ocean liners (with Cunard contributing fifteen ships and White Star ten).  Both Cunard and White Star were in dire financial trouble, and were looking to complete enormous liners: White Star had Hull 844 – RMS "Oceanic III" – and Cunard had Hull 534, which would later become  . RMS "Sylvania was an ocean liner built in 1957 by John Brown & Co (Clydebank), Glasgow, Scotland for the United Kingdom-based shipping company Cunard Line.  She was the last Cunard Line vessel built specifically for transatlantic crossings.  The ship was later heavily rebuilt as a cruise ship, and sailed under the names SS "Fairwind, SS "Sitmar Fairwind, SS "Dawn Princess and SS "Albatros before being scrapped in 2004.  She was renamed SS "Genoa for her last voyage. Queen Elizabeth 2, often referred to simply as QE2, is an ocean liner built for the Cunard Line which was operated by Cunard as both a transatlantic liner and a cruise ship from 1969 to 2008.  She was designed for the transatlantic service from her home port of Southampton, UK, to New York, and was named after the earlier Cunard liner  .  She served as the flagship of the line from 1969 until succeeded by  in 2004.  Designed in Cunard's then headquarters and regional offices in Liverpool and Southampton respectively, and built in Clydebank, Scotland, she was considered the last of the great transatlantic ocean liners until the construction of the Queen Mary 2 was announced. RMS "Queen Mary 2 (also referred to as the QM2") is a transatlantic ocean liner.  She is the largest and only major ocean liner built for the British Cunard Line since "Queen Elizabeth 2" in 1969, the vessel she succeeded as flagship of the Cunard Line. RMS "Caronia" was a  gross register tons (GRT) passenger ship of the Cunard Line (then Cunard White Star Line).  Launched on 30 October 1947, she served with Cunard until 1967.  She was nicknamed the "Green Goddess".  She is credited as one of the first "dual-purpose" built ships: suited to cruising, but also capable of transatlantic crossings.  After leaving Cunard she briefly served as SS "Caribia" in 1969, after which she was laid up in New York until 1974 when she was sold for scrap.  While being towed to Taiwan for scrapping, she was caught in a storm on 12 August.  After her tow lines were cut, she repeatedly crashed on the rocky breakwater outside Apra Harbor, Guam and broke into three sections. Philip Plisson (born January 27, 1947, Orléans, France) is a French photographer best known for his maritime photography.  Together with his son Guillaume, who is also a photographer, he set up the publishing company Pêcheur d'Images.  He has produced numerous books including collections of photographs featuring Brittany, Ireland, Scotland and the ocean liner "Queen Mary 2".  His 65th book, "Les Marées", was named Maritime Book of the Year at the 2012 Paris Boat Show. The RMS "Franconia" was an ocean liner operated by the Cunard Line from 1922 to 1956.  She was second of three liners named "Franconia" which served the Cunard Line, the others being RMS "Franconia" built in 1910 and the third "Franconia" in 1963. SS "Ivernia" was a British ocean liner owned by the Cunard Line, built by the company Swan Hunter & Wigham Richardson of Newcastle upon Tyne, England, and launched in 1899.  The "Ivernia" was one of Cunard's intermediate ships, that catered to the vast immigrant trade.  Together with her sister ship SS "Saxonia", the "Ivernia" worked on Cunard's service from Liverpool to Boston and then later on the immigrant run the Cunard Line had established from Fiume and Trieste to New York City. RMS "Queen Mary" is a retired ocean liner that sailed primarily on the North Atlantic Ocean from 1936 to 1967 for the Cunard Line (known as Cunard-White Star Line when the vessel entered service).  Built by John Brown & Company in Clydebank, Scotland, "Queen Mary", along with  , were built as part of Cunard's planned two-ship weekly express service between Southampton, Cherbourg and New York.  The two ships were a British response to the express superliners built by German, Italian and French companies in the late 1920s and early 1930s.  "Queen Mary" was the flagship of the Cunard Line from May 1936 until October 1946 when she was replaced in that role by "Queen Elizabeth".
Answer: Queen Mary 2