4. In response to Covid-19, the Fed rapidly expanded its balance sheet. a) How did they do this? Describe the process of a central bank expanding its balance sheet. b) What are the consequences of such a central bank policy? What is the goal? c) Is such a policy sustainable indefinitely? How do you know? 4. In response to Covid-19, the Fed rapidly expanded its balance sheet. a) How did they do this? Describe the process of a central bank expanding its balance sheet. b) What are the consequences of such a central bank policy? What is the goal? c) Is such a policy sustainable indefinitely? How do you know