GENERAL KNOWLEDGE

Detailed explanation-1: -Archduke Franz Ferdinand was the heir to the Austro-Hungarian throne. In the summer of 1914, he and his wife Sophie travelled to Bosnia, a province of the multinational Austro-Hungarian Empire. On Sunday, 28 June, the couple were assassinated in the capital, Sarajevo, by Bosnian-Serb nationalists.

Detailed explanation-2: -On July 28, 1914, one month to the day after Archduke Franz Ferdinand of Austria and his wife were killed by a Serbian nationalist in Sarajevo, Austria-Hungary declares war on Serbia, effectively beginning the First World War.