(A) The provisions of this chapter shall not be construed to tax the military pay or allowances of members of the armed forces of the United States, or the income of religious, fraternal, charitable, scientific, literary or educational institutions to the extent that such income is derived from tax exempt real estate, tax exempt tangible or intangible property or tax exempt activities.
(B) The tax provided for herein shall not be levied on the personal earnings of any natural person under 18 years of age.
(C) Mentally retarded and developmentally disabled employees earning less than the minimum hourly wage while employed at government-sponsored sheltered work-shops shall be exempt from the levy of the tax provided herein.