please answer A-C on #4 as it is a multiple summary question. thanks.

4. The nation of Warhawk has a tax rate of 5% on the first 20,000 walops (the national currency) of taxable income, then 20% on the next 30,000 walops, then 50% on all taxable income above 50,000 walops. Warhawk provides a 5,000-walop exemption per family member. a. Jamil's family has three members and earns 60,000 walons per year. Calculate the family's marginal and average tax rates. b. Boba's family has five members and earns 100,000 walops per year. Calculate the family's marginal and average tax rates. c. Suppose that Warhawk changed its tax code to a flat tax of 30% with a 10,000 -walop per family member exemption. Would this change in the tax system make the system more progressive, more regressive, or neither