Which of the Following Is a Difference Between "Quantitative Easing

Which of the following is a difference between "quantitative easing" and ordinary open-market operations?

A) There is no difference between the two policy tools.
B) Open-market operations are done in order to lower interest rates;quantitative easing is merely intended to increase bank reserves.
C) Quantitative easing is focused exclusively on U.S.government bonds;open-market operations also include the buying and selling of debt issued by government agencies and government-sponsored entities.
D) Open-market operations involve forward commitment;quantitative easing is intentionally vague to maintain flexibility.