The Second Battle of the Marne Was Significant Because It

The Second Battle of the Marne was significant because it

A) was the first time American troops saw action in France.
B) marked a temporary reversal of the Allies progress in Europe that extended the war by at least six months.
C) was the first time American troops fought by themselves.
D) saw the first use of combat aircraft.
E) marked the beginning of a German withdrawal that was never reversed.