Answer: D. Great Britain.
Explanation: In 1914, the British Royal Navy was the largest and most powerful in Europe. Germany tried to create a Navy similar in power to the British one but its attempt failed. According to "A Naval History of World War I" by Halpern, Britain was the strongest naval force in 1914, followed by Germany and France. The strength of navies was measured by the number of dreadnought battleships, battlecruisers and other types of warships.