A Central Argument of New Keynesian Theories of Unemployment Is

A central argument of New Keynesian theories of unemployment is that

A) labour markets will clear and unemployment will thereby be eliminated.
B) monetary policy is rarely effective at reducing unemployment.
C) even competitive labour markets cannot be relied upon to eliminate involuntary unemployment.
D) all unemployment is caused by government intervention in the economy.
E) all unemployment arises from firms being unwilling to hire extra workers.