Which of the Following Statements About Quantitative Easing Is Most

Which of the following statements about quantitative easing is most accurate?

A) Quantitative easing occurred in three rounds from 2009 to 2014, with the Fed buying nearly $4 trillion in securities.
B) Quantitative easing has become one of the permanently recognized tools of monetary policy.
C) Quantitative easing significantly lowered interest rates in the aftermath of the financial crisis.
D) Quantitative easing is the new official name for open-market operations.