Which of the Following Defines an Inflationary Gap

Which of the following defines an inflationary gap?

A) The amount by which withdrawals exceed injections at the full- employment level of national income
B) The amount by which equilibrium national income exceeds the full- employment level
C) The amount by which national income exceeds national expenditure at the full- employment level of national income
D) The amount by which national expenditure exceeds national income at the full- employment level of national income