What can be concluded from Milton Friedman and Edmund Phelps’ expectat

What can be concluded from Milton Friedman and Edmund Phelps’ expectations-augmented Phillips curve?

A) that there is no long run tradeoff between unemployment and inflation
B) that there is a short run tradeoff between unemployment and inflation
C) that there are two types of Phillips curves
D) all of the above
E) none of the above

ANSWER

D