(a) There are hereby levied and imposed, subject to all other provisions of this Chapter, the following Privilege Taxes for the purpose of raising revenue to be used in defraying the necessary expenses of the City, such taxes to be collected by the Tax Collector:
(1) A Privilege Tax upon persons on account of their business activities, to the extent provided elsewhere in this Article, to be measured by the gross income of persons, whether derived from residents of the City or not, or whether derived from within the City or from without.
(2) A Privilege Tax upon certain persons for the privilege of occupancy of real property, in accordance with the provisions of Section 3.04-440.
(3) A Privilege Tax upon persons for the privilege of selling jet fuel, whether derived from residents of the City or not, or whether derived from within the City or from without, in accordance with the provisions of Section 3.04-422.
(b) Taxes imposed by this Chapter are in addition to others. Except as specifically designated elsewhere in this Chapter, each of the taxes imposed by this Chapter shall be in addition to all other licenses, fees, and taxes levied by law, including other taxes imposed by this Chapter.
(c) Presumption. For the purpose of proper administration of this Chapter and to prevent evasion of the taxes imposed by this Chapter, it shall be presumed that all gross income, or gallons sold, is subject to the tax until the contrary is established by the taxpayer.
(d) Limitation of exemptions, deductions, and credits allowed against the measure of taxes imposed by this Chapter. All exemptions, deductions, and credits set forth in this Chapter shall be limited to the specific activity or transaction described and not extended to include any other activity or transaction subject to the tax.