Which of the Following Is True About Grease Payments

Which of the following is true about grease payments?

A) Grease payments are more offensive than bribes.
B) Grease payments facilitate performance of duties that the recipients are not obligated to perform.
C) A grease payment is a form of penalty.
D) Both the U.S. law and OECD convention include language that opposes grease payments.
E) Grease payments are technically bribes, however they are distinguishable from bribes.