Which event officially ended World War I?

The event that officially ended World War I is the Treaty of Versailles. This treaty was signed on June 28, 1919, and it formally concluded hostilities between the Allied Powers and Germany. The treaty included various terms and provisions that aimed to ensure a lasting peace and to address the territorial and political adjustments necessary following the war. Key elements of the Treaty of Versailles included reparations that Germany was required to pay, territorial losses for Germany, and the establishment of the League of Nations, an international organization aimed at preventing future conflicts.

The other choices do not relate to the conclusion of World War I. The Boston Tea Party was a protest against British taxation in 1773, the Pearl Harbor attack was a critical event in World War II, happening in 1941, and the Emancipation Proclamation was an executive order issued during the American Civil War in 1863 that aimed to free enslaved people in the Confederate states. Each of these events is significant in American history but does not pertain to the end of World War I.