As used in this article:
(a) "Insurance company" means any individual, firm or corporation engaged in the business of selling insurance in this state, excepting only: (1) Clubs or associations organized under the laws of this state which sell insurance to their members and (2) companies engaged exclusively in the sale of life or accident and sickness insurance.
(b) "Insurance agent" means any individual, firm or corporation appointed by an insurance company, as defined herein, whose exclusive activity in this field is in behalf of a single insurance company and who is authorized by that company to solicit insurance or to negotiate insurance on its behalf, and who is authorized by the insurance company to effectuate and countersign insurance contracts on its behalf.