“Representation case” means the representation of any person, client, principal, or third person, with compensation, in any matter before any state agency where the action or non-action of the state agency involves the exercise of substantial discretion; but representation case does not mean or include (a) any communication initiated by a legislator on behalf of a constituent or other member of the public for which no compensation is received or to be received, or (b) preparation and filing of tax returns or other governmental forms, or (c) participation in tax audit negotiations, or (d) any activity of a state officer or employee in carrying out the duties of his or her office or employment, or (e) a preliminary inquiry by any person into a matter before a state agency.