The correct option is A
The ultimatum of July 23, 1914 was a document presented by the Austro-Hungarian Ambassador to the Serbian Government in Belgrade that day. Drafted with care by the diplomats of the Austro-Hungarian Empire, supposed the answer of this to the assassination of the heir to the imperial throne, Archduke Franz Ferdinand of Austria, happened in Sarajevo on June 28. This late reaction was the fruit of the agreement between the empire and its main ally, the German Empire, reached on July 7. After several weeks of discussions between the imperial leaders, supporters of the war with Serbia - considered responsible for the assassination - managed to finally convince the most reluctant to unleash it and entrusted the writing of an ultimatum to a junior member of the diplomatic corps, with recognized talent for these tasks. He drafted a document designed to be rejected by the Government of Belgrade. The document was presented to the Serbian authorities on the 23rd of the month; the Serbian response was labeled as unacceptable by Austro-Hungarian diplomacy. This rejection led to the breakdown of relations between Vienna and Belgrade and then the beginning of hostilities between the two countries, in which the allies of each of them soon took part: the Reich on the Austro-Hungarian side and the Serbian Triple Entente .
