A. Receipts from transactions in interstate commerce may be deducted from gross receipts to the extent that the imposition of the gross receipts tax would be unlawful under the United States constitution.

B. Receipts from transactions in interstate commerce may be deducted from governmental gross receipts.

C. Receipts from transmitting messages or conversations by radio other than from one point in this state to another point in this state and receipts from the sale of radio or television broadcast time when the advertising message is supplied by or on behalf of a national or regional seller or advertiser not having its principal place of business in or being incorporated under the laws of this state, may be deducted from gross receipts. Commissions of advertising agencies from performing services in this state may not be deducted from gross receipts under this section.