It was repeatedly defeated by the Germans and suffered extremely high casualties is the best sentence that describes the experience of the russia in world war 1.
<u>Explanation:</u>
- Germany declared war on France and Russia. Russia entered with the largest army in the world.
- Russia fully mobilized its soldiers for the world war but it could not provide the ammunition artillery for all of its soldiers though it had many soldiers it can't able to provide instruction and weapons for them to fight in the war.
- Thus due to the lack of weapons and instructions to soldiers, the Russians were defeated by the German army severely and there were more casualties than normal.
I believe it would/can be C and A
Hope it helps :D