4. Consider the following hypothetical marginal tax rate schedule for the Personal Income Tax (PIT). Tax Rate Income From $0 to $20,000 From $20,000 to $50,000 From $50,000 to $100,000 From $100,000 to $200,000 Greater than $200,000 10% 20% 30% 40% Also, there is a Canada Workers Benefit (CWB) with the following features: - A wage subsidy of 25 percent up to an income of $20,000 - For incomes from $20,000 to $30,000 the CWB is $5,000. - For incomes above $30,000 the CWB is taxed back at a rate of 10% a) Determine the income level at which the CWB disappears. (5) b) Draw a table like this: Income CWB ($) PIT ($) Marginal Tax Average Tax Rate (MTR) (%) Rate (ATR) (%) $15,000 $40,000 $70,000 $300,000 Fill in the table, taking account of both the PIT and the CWB on the MTR and ATR. (10) c) Explain why economists like the CWB so much