Step 1: Overview of the Crimean War and Cavour's Role.
The Crimean War (1853-1856) was fought between Russia and an alliance of France, Britain, the Ottoman Empire, and Sardinia. Cavour, the Prime Minister of Sardinia, announced his participation on the side of France in order to gain support for the unification of Italy.
Step 2: Analysis of options.
- (A) France: Correct, Cavour sought to strengthen his relationship with France and participated in the war on their side.
- (B) Austria: Incorrect, Austria did not participate in the Crimean War on the side of France.
- (C) Germany: Incorrect, Germany was not involved in the Crimean War as a unified nation at this time.
- (D) Poland: Incorrect, Poland was not a key player in the Crimean War.
Step 3: Conclusion.
The correct answer is (A) France.