Congress passes a law which grants federal funds to states for the purchase of wind powered electricity generators to be used to offset the pollution created by coal powered electricity plants. Paragraph 7 of the law provides that "no state shall be eligible to receive such funds unless said state shall have imposed a tax of seven cents on every package of cigarettes sold in such state in addition to whatever cigarette tax is already in existence at the time that this act takes effect."

From which of the following does Congress derive the power to enact paragraph 7 of the law?

Select one:

a. The congressional taxing power.

b. The congressional spending power.

c. The general federal police power.

d. The congressional power to regulate interstate commerce.