During 2018, the Smiths and the Joneses both filed joint tax returns. For the tax year ended December 31,2018, the Smiths' taxable income was $126,000, and the Jones had total taxable income of $63,000. a. Using the federal tax rates given in Table 1.2, , for married couples filing joint returns, calculate the taxes for both the Smiths and the Joneses. b. Calculate and compare the ratio of the Smiths' to the Joneses' taxable income and the ratio of the Smiths' to the Joneses' taxes. What does this demonstrate about the federal income tax structure? The ratio of the Smiths' to the Joneses' taxes is 2.73 . (Round to two decimal places.) What does this demonstrate about the federal income tax structure? (Choose the best answer below.) A. Those who earn lower incomes pay a higher proportion of their income in taxes. B. Those who earn higher incomes pay a lower proportion of their income in taxes. C. Those who earn higher incomes pay a higher proportion of their income in taxes. D. Everyone pays the same proportion of their income in taxes