When Inflationary Expectations Are Added to the Phillips Curve, the Nonaccelerating

When inflationary expectations are added to the Phillips curve, the nonaccelerating inflation rate of unemployment is defined as the unemployment rate at which the

A) inflation rate is always zero.
B) actual inflation rate exceeds the expected inflation rate.
C) actual inflation rate is less than the expected inflation rate.
D) actual inflation rate equals the expected inflation rate.