7. The provisions of this act shall preempt a political subdivision from regulating, requiring or issuing any registration, license plate or marker or surety registration of any towing company. This section shall not limit the existing authority of a political subdivision to:
a. License and collect a general and nondiscriminatory tax upon all businesses;
b. License and collect a tax upon towing operations domiciled within its jurisdiction; or
c. Impose any additional requirements or conditions as part of any contract to perform towing and recovery services for that jurisdiction.