What forced russia to discontinue fighting in world war i
a-lack of manpower
b-economic ruin
c-inept leadership
d-a revolution

The answer is C.

The Russian leaders were so clumsy and irresponsible. They poorly trained there troops and supplied so little that it caused the Russian army to become null and inoperative. Russian leaders had poor decision making, thus, destroying the trust of the troops. This led to the desertion of Russian troops and even the assassination of their own leaders. The soldiers even formed little groups that would not anymore follow orders but would decide by their own what to do during the war.