Which of the Following Statements Is Correct

Multiple Choice

Which of the following statements is correct?

A) Milton Friedman's theory of the natural rates of unemployment and output has been highly influential since it describes the limits to the trade-off between inflation and unemployment.
B) Milton Friedman's main concern in advancing the concept of the natural rates of output and unemployment was to illustrate a limitation on monetary policy.
C) Milton Friedman's main concern in advancing the concept of natural rates of output and unemployment was to define a limitation on fiscal policy.
D) Both a and b
E) Both a and c