Which of the following statements regarding intermediate sanctions is correct?

a. The excise tax is imposed on the exempt organization and on disqualified persons.

b. Intermediate sanctions are self-assessing (i.e., calculated and paid by the taxpayer, not imposed by the IRS).

c. Both a first-level tax and a second-level tax may apply.

d. The corporate Federal income tax rates apply in calculating the amount of the tax liability.