Milton Friedman and Edmund Phelps Contributed Which Insight(s)to Phillips Curve

Multiple Choice

Milton Friedman and Edmund Phelps contributed which insight(s) to Phillips curve analysis?

A) that firms and workers care about nominal,not real wages
B) that wage changes have a one-to-one relationship with changes in expected inflation
C) that,in the long run,prices are flexible,so unemployment cannot remain above zero
D) all of the above
E) none of the above