Which One of the Following Statements Is Not a True

Which one of the following statements is not a true statement with regard to Phillips curve with inflation-unemployment trade-off?

A) Each Phillips curve assumes a given expected inflation.
B) Flatter the short-run aggregate supply curve, flatter is the given Phillips curve.
C) A higher expected inflation will cause an upward shift of the Phillips curve.
D) In the long-run, the Phillips curve is a vertical line. because expected inflation is zero.