Question 4 (12 marks length guide: about 2-3 pages including graphs) Use the IS-LM and/or AS-AD models to illustrate your answers to the following. To counteract the COVID-19 pandemic, the Reserve Bank of Australia has eased its monetary policy. a) What are the key monetary policy changes that have been made since March 2020? (4 marks) b) Why has the RBA had to do more than just cut the cash rate? (2 marks) The Australian government's budget papers in October 2020 explain that its fiscal deficit in 2020-21 is expected to increase from about 4% to 11.0% of GDP, and that government net debt is expected to increase from about 25% to 44% of GDP by June 2024. c) How and why has the government increased its deficit by so much? (4 marks) d) Should we be concerned about the increase in government debt? (2 marks)