Which of the following statements is incorrect regarding the taxation of C corporations?
a. The highest corporate marginal tax rate is 39%.
b. Taxable income of a personal service corporation is taxed at a flat rate of 39%.
c. A tax return must be filed whether or not the corporation has taxable income.
d. Unlike those applicable to individuals, the marginal tax rate brackets for corporations are not adjusted for inflation.
e. None of the above.