Statement I: The highest marginal federal personal income tax rate is 30 percent.
Statement II: The marginal tax rate is found by dividing additional taxes paid by additional taxable income.

A) Statement I is true and statement II is false.
B) Statement II is true and statement I is false.
C) Both statements are true.
D) Both statements are false.

Statement I is false because the highest marginal federal personal income tax rate in the United States exceeds 30 percent. As of my last update, it stands at 37 percent for incomes above certain thresholds. Statement II is true as the marginal tax rate indeed represents the rate at which the last dollar of income is taxed, calculated by dividing the additional taxes paid by the additional taxable income.