Isla is a single taxpayer. For the current tax year, her adjusted gross income is $320,000. Her taxable income is $270,000. In addition, she received $14,000 of interest from municipal bonds she owns and a gift of $10,000 from her parents. [Current Tax Year = 2018]

a. Islas marginal tax rate is 35.0%; average tax rate is 26.0%, effective tax rate is 23.9%.

b. Islas marginal tax rate is 26.0%; average tax rate is 35.0%, effective tax rate is 25.0%.

c. Islas marginal tax rate is 23.9%; average tax rate is 35.0%, effective tax rate is 26.0%.

d. Islas marginal tax rate is 35.0%; average tax rate is 25.0%, effective tax rate is 23.9%.