Which of the following statements describes a permanent book/tax difference?

A. An expense that is reported on this year's income statement but is deducted on next year's tax return
B. A revenue item that is included in current year taxable income but is not reported on the income statement until next year
C. An expense that is never deductible
D. A revenue item that is reported on this year's income statement but will not be included in taxable income until an indefinite future year.