Which of the following statements is not correct?

a.Corporations must estimate and prepay their income taxes through quarterly tax deposits.

b.At the end of the year, when the worksheet is prepared, the Income Tax Expense account is adjusted only if the corporation owes additional taxes.

c.Income Tax Expense may be shown as an operating expense on a corporation's income statement.

d.On a corporate income statement, the tax effects of each extraordinary item is offset against each gain or loss to show the effect net of taxes.'