Answer: a. The United Kingdom had the largest navy
Step-by-step explanation:
For hundreds of years up until the emergence of the United States as the world's foremost naval power, Britain held the title of the largest and most destructive navy in the world.
They used this to protect Britain from invasion at a time when European countries were regularly fighting and invading each other.
As soon as WWI broke out, the British navy set about destroying all German naval vessels and blockading Germany. Germany responded by using submarines and this led to the British incurring large losses as the Germans knew that it was the British they had to defeat on the seas if they were to win the war.