Explanation:
England (Britain) was Napoleon's most persistent adversary:

Naval supremacy: The British Royal Navy defeated France at Trafalgar (1805), preventing invasion

Economic warfare: Britain's blockade crippled Napoleon's Continental System

Never occupied: Unlike most European nations, England remained unconquered


Other Options Analysis:

A. Prussia: Defeated by Napoleon at Jena-Auerstedt (1806) and occupied until 1813

B. Australia: Irrelevant (was a British colony, not involved in Napoleonic Wars)

C. Russia: Initially defeated (1807 Treaty of Tilsit), though Napoleon's 1812 invasion failed later