By the time american troops entered world war i, the allies
a. were determined to win the war without any .
b. were using trench warfare successfully against the germans.
c. were exhausted after years of fighting.
d. were preparing to attack germany.

By the time American troops entered World War I, the Allies were preparing to attack the Germans. The correct option among all the options that are given in the question is the last option or option "D". The joining of war by the Americans was a major turning point of the war. It boosted the moral of the Allies.