Option 1: The Treaty of Trianon is not the correct answer. The Treaty of Trianon was signed in 1920 and dealt with the aftermath of World War I, specifically the dissolution of the Austro-Hungarian Empire.

Option 2: The Treaty of Versailles is not the correct answer. The Treaty of Versailles was also signed in 1920 and dealt with the aftermath of World War I, specifically the punishment of Germany.

Option 3: The Treaty of Paris is the correct answer. The Crimean War came to an end with the signing of the Treaty of Paris in 1856. This treaty was signed by Russia on one side, and France, Britain, Sardinia, and the Ottoman Empire on the other side. It resulted in several terms, including the neutralization of the Black Sea and the independence and sovereignty of Ottoman Empire over Moldavia and Wallachia.

Option 4: The Treaty of St. Germain is not the correct answer. The Treaty of St. Germain was signed in 1919 and dealt with the dissolution of the Austro-Hungarian Empire.

In conclusion, the correct answer is option 3, the Treaty of Paris.