Which of the following events precipitated the First World War?

A) The seizure of Shandong by Japan
B) The assassination of the heir to the Austro-Hungarian throne
C) The revelation of the secret German war plan against France
D) The exposure of Russian Czar Nicholas II's affair with his German chambermaid

Austro-Hungarian Throne

The imperial and royal throne of the Austro-Hungarian Empire, which was a dual monarchy in Central Europe from 1867 to 1918.

Shandong

A coastal province of China known for its significant historical, cultural, and geographical features, including being the birthplace of Confucius.

German War Plan

Strategic military initiatives and operations developed by Germany, particularly noted during World Wars I and II.