Answer :
Final answer:
Austria declared war on Serbia after the latter failed to completely meet a list of demands following the assassination of Archduke Franz Ferdinand. This move, backed by Germany's support, marked the beginning of World War I as alliances between countries drew more into the conflict. So the correct option is A) Austria.
Explanation:
After the assassination of Archduke Franz Ferdinand, Europe descended into war in the summer of 1914. The country that declared war on Serbia was Austria. This action came after Austria issued a list of ten ultimatums to Serbia, which Serbia failed to meet completely. Emboldened by Germany's promise of support, often referred to as the "blank check," Austria felt confident in its position.
Germany's role soon expanded as it declared war on Russia to protect Austria, following Russia's mobilization of forces in defense of Serbia. The complex system of alliances between these nations ensured that the conflict quickly escalated, drawing in additional powers and eventually leading to World War I.
