On each operator there is hereby levied an annual highway privilege tax for each of the following motor vehicles as follows:
On each hearse and on each ambulance, per annum.....$25.00
On each church-owned bus, per annum.....10.00
On each school bus used exclusively as such, excluding school buses owned by a school district in the state, per annum.....10.00
Provided, however, that any motor vehicle used otherwise, and on which there has been paid the privilege tax at a higher rate as provided in this article, may also be used as a school bus without the further payment of a road and bridge tax, and provided further, that in the event a person pays a flat privilege tax of Ten Dollars ($10.00), as levied in this subparagraph (c), and later desires to use his school bus for other purposes, and purchases a privilege tag for same as provided in this article, he shall be given credit on his new privilege tag purchased for the unearned part of the privilege tax paid.
On each taxicab, per annum.....35.00