When a Bond Payable Is Issued at a Premium,subsequent Amortization

When a bond payable is issued at a premium,subsequent amortization of the premium does which of the following?

A) Increases interest expense.
B) Decreases the book value of the bonds.
C) When the effective-interest method is used,the amount of amortization would decrease for each year the bond approaches maturity.
D) The amount of amortization would be added to net income to arrive at cash flows from operating activities.