Final answer:
During World War I, the war became a war of attrition, with both sides trying to wear down the other's forces through prolonged battles and heavy casualties.
Step-by-step explanation:
In World War I, the war became a war of attrition, which means that both sides tried to wear down and exhaust the other side's forces.
The correct answer to your question is option C. The Allies tried to wear down the German forces with a series of repeated, continued attacks on a position until the Germans no longer had sufficient manpower to defend the position.
Throughout the war, both sides experienced heavy casualties and massive loss of life in the prolonged and deadly battles, such as the Battle of Verdun and the Battle of the Somme.