(A) Mexico and US
(B) ** Germany and US
(C) Germany and Mexico
(D) Great Britain and US
EXPLANATIONS BELOW
Concept note-1: -In May 1916, the German government issued a pledge to the United States that the Imperial navy would not attack passenger ships and would further allow the crew of merchant ships which carried war material to exit their vessels before they would be sunk.
Concept note-2: -On May 6, the German government signed the so-called Sussex Pledge, promising to stop the indiscriminate sinking of non-military ships. According to the pledge, merchant ships would be searched, and sunk only if they were found to be carrying contraband materials.
Concept note-3: -The Sussex Pledge was a promise made by Germany to the United States in 1916, during World War I before the latter entered World War I. Early in 1915, Germany had instituted a policy of unrestricted submarine warfare, allowing armed merchant ships but not passenger ships to be torpedoed without warning.
Concept note-4: -The loss of life due to the sinking of the Sussex also caused Germany to promise that the safety of the crew and passengers of any ship sunk would be taken care of.
Concept note-5: -President Woodrow Wilson threatened to cut diplomatic relations, and Germany responded with the Sussex Pledge, through which they promised not to target civilian liners. In 1917, the Germans renounced the Sussex Pledge and sunk several American ships, leading to U.S. entry into World War I.