(A) The Lusitania
(B) ** Submarines or U-boats
(C) German flotilla
(D) The USS Maine
EXPLANATIONS BELOW
Concept note-1: -Germany retaliated by using its submarines to destroy neutral ships that were supplying the Allies. The formidable U-boats (unterseeboots) prowled the Atlantic armed with torpedoes.
Concept note-2: -Before the start of World War II, Germany started building U-boats and training crews, labeling these activities as “research” or concealing them using other covers.
Concept note-3: -On January 31, 1917, Germany announces the renewal of unrestricted submarine warfare in the Atlantic as German torpedo-armed submarines prepare to attack any and all ships, including civilian passenger carriers, said to be sighted in war-zone waters.
Concept note-4: -German submarine U-1 was the first U-boat (or submarine) built for Nazi Germany’s Kriegsmarine following Adolf Hitler’s abrogation of the terms of the Treaty of Versailles in 1935, which banned Germany possessing a submarine force. Part of: U-boat School Flotilla. 1 July 1935 – 1 February 1940.