(A) ** with the convoy system
(B) with the Meuse-Argonne campaign
(C) by causing a revolution on the Eastern Front
(D) by breaking the stalemate between the two countries
EXPLANATIONS BELOW
Concept note-1: -How did the Allies counteract German unrestricted submarine warfare? The developed a convoy system of merchant vessels that were protected by Allied destroyers. This man was chosen to go overseas and command the American Expeditionary Force.
Concept note-2: -In response to the U-Boat attacks, Allied merchant ships sailed in groups, called convoys, escorted by warships. The convoys were harder for U-Boats to find and attack, but the U-Boats still posed a terrifying threat. By the end of 1917, 3, 170 Allied and neutral ships, totaling nearly six million tons, were sunk.
Concept note-3: -Aircraft radar also evolved to became one the best ways to hunt submarines. Towards the end of WWII radar equipped aircraft is credited for most of Allied kills against U-Boats. Enemy submarines had great difficulty seeing the planes above them until it was too late.
Concept note-4: -On May 4, 1916, Germany responds to a demand by U.S. President Woodrow Wilson by agreeing to limit its submarine warfare in order to avert a diplomatic break with the United States.
Concept note-5: -This ‘unrestricted submarine warfare’ angered neutral countries, especially the United States. The tactic was abandoned on 1 September 1915, following the loss of American lives in the torpedoed liners Lusitania and Arabic.