What is unrestricted submarine warfare and which nation implemented it in WWI?

• A. Sinking ships without warning to choke enemy supply routes; implemented by Germany.
• B. Attacking only military ships with prior warning; implemented by Britain.
• C. Using submarines for rescue operations at sea; implemented by France.
• D. Ceasing submarine warfare to avoid civilian casualties; implemented by the United States.

Answer: (A)

Unrestricted submarine warfare means using submarines to sink ships without warning, aiming to cut off an enemy’s supply lines and cripple its war effort, even if civilian or neutral vessels are involved. In World War I, Germany adopted this approach to choke Britain’s maritime imports and force a quicker victory, resuming it in 1917 after earlier, more restrained U-boat actions. This policy drew heavy international backlash and helped push the United States toward involvement in the war after several ships with American passengers were sunk.

That’s why the best description is sinking ships without warning to choke enemy supply routes, implemented by Germany. Britain, France, and the United States did not initiate this policy in the same way during WWI.