Why was Russia drawn into conflict with Germany after Austria-Hungary declared war on Serbia?
A. Russia had an alliance with Serbia, and Germany had an alliance
with Austria-Hungary.
B. Both Russia and Germany hoped to capture Serbia before Austria-
Hungary could invade.
C. Russia broke its alliance with Germany by refusing to aid Austria-
Hungary against Serbia.
O D. Russia convinced France to invade Germany to stop those
countries from joining the attack on Serbia.

A. Russia had an alliance with Serbia, and Germany had an alliance  with Austria-Hungary.

Explanation:

Russia had strong relations with Serbia at the time and has often taken a position to defend Serbia. Connected by the Slavic heritage and Orthodox Christian faith, both countries felt a pan-Slavic attachment to each other.

France and Russia had felt the obligation to protect Serbia. As such, they both stepped into the armed conflict forming an alliance with Serbia, as soon as Austria-Hungary declared the war. Russia started mobilizing the army timidity and ignored Germany’s demands to stop. Finally, Germany, an ally of the Austrian-Hungarian Empire, declared war on Russia.