How did the annexation of Bosnia and herzegovina in 1908 intensify the rivalry between Austria-Hungary and Serbia

Serbia vowed to take back the annexed territory from Austria-Hungary, is the right answer.

Explanation:

A controversy emerged between the Dual Monarchy and Turkey after the annexation of Bosnia and Herzegovina. The annexation by Austria-Hungary led to international complications that threatened to end the European war. This is known as the Bosnian Crisis.

The annexation of Bosnia and Herzegovina angered Serbia and the Balkans. Moreover, Austria-Hungary's invasion of Serbia made Russia provide aid to Serbia and Germany came to support Hungary.