a. What is the main difference between Keynesian and Classic theory? b. What are the critics of Keynesian and classic theory c. Why is the investment demand curve less stable than the consumption and saving schedules? What are the basic determinants that can shift the investment demand curve? d. In the case of the COVID-19 pandemic in Indonesia, give a brief and deep explanation about how do the Government cope with it? Do you think its a Keynesian or classical theory that Government does?.