Advantages the United States brought to the Allied cause included everything listed except:

Aa boost in morale
Bsupplies and equipment
Cthe Russian surrender
Dthe strength to drive the Germans back

Verified Answer :

Advantages the United States brought to the Allied cause included everything listed (a boost in morale, supplies and equipment, and the strength to drive the Germans back), except C) the Russian surrender. 

Answer:

C. The Russian surrender