Final answer:
In November 2008, the Federal Reserve's initiation of quantitative easing resulted in a dramatic increase in the monetary base.
Step-by-step explanation:
When the Federal Reserve began its policy of quantitative easing (QE) in November 2008, there was a dramatic increase in the monetary base. QE was an unconventional monetary policy adopted due to the limitations of traditional policy tools, as short-term interest rates were already near-zero. QE involved purchasing long-term securities, which significantly expanded the monetary base and was intended to stimulate aggregate demand by making credit more available.