why did russia send troops to the border of austria - hungary in 1914?\no austria - hungary had invaded…

why did russia send troops to the border of austria - hungary in 1914?\no austria - hungary had invaded serbia, and russia was in an alliance with serbia.\no austria - hungary was threatening to invade russia.\no austria - hungary was sending its people to live in russia.\no austria - hungary needed help resisting a german invasion.

why did russia send troops to the border of austria - hungary in 1914?\no austria - hungary had invaded serbia, and russia was in an alliance with serbia.\no austria - hungary was threatening to invade russia.\no austria - hungary was sending its people to live in russia.\no austria - hungary needed help resisting a german invasion.

Answer

Answer:

A. Austria - Hungary had invaded Serbia, and Russia was in an alliance with Serbia.

Brief Explanations:

In 1914, Austria - Hungary declared war on Serbia. Russia, having an alliance with Serbia, mobilized troops near the border of Austria - Hungary in support of its ally. This was a key event leading to the start of World War I.