What Struck a Blow to American Morale Just as It

What struck a blow to American morale just as it was improving with the arrival of French troops?

A) Americans realized that France was acting out of self-interest rather than idealism.
B) General Benedict Arnold turned traitor and tried to hand over West Point to the British.
C) General Nathanael Greene lost Georgia to the British.
D) French soldiers proved to be an unreliable fighting force.
E) General Lafayette refused any longer to command American troops.