In 2021, Jack and Jill Smith have AGI of $120,000. Jack and Jill are both 72 years old and are both blind. They have no dependents and their itemized deduction (ie. from AGI) amounts to $22,000. They file a joint return. (show work please)

a. Determine the Smith's taxable income for 2021. (show work)

b. What is the Smith's marginal tax rate.

c. Determine the Smith's federal income tax for 2021. (show work)