The following activities, when performed by a municipality, are considered to be activities of a person engaged in business for the purposes of this Chapter, and not excludable by reason of Section 12-270:
(a) rental, leasing, or licensing for use of real property to other than another department or agency of the municipality.
(b) producing, providing, or furnishing electricity, electric lights, current, power, gas (natural or artificial), or water to consumers or ratepayers.
(c) sale of tangible personal property to the public, when similar tangible personal property is available for sale by other persons, as, for example, at police or surplus auctions.