The party against whom the administrative action is taken may be represented at hearing, as follows:
(a) Individuals may appear on their own behalf;
(b) A member of a partnership or joint venture may appear on behalf of the partnership or joint venture;
(c) A bona fide officer may appear on behalf of a corporation or association upon a showing of adequate authorization;
(d) An attorney who files a notice of appearance with the hearing officer may represent any party. For purposes of this paragraph, an attorney is defined as a member of the bar of a federal court or of the highest court of any state or territory of the United States; or
(e) An individual not included within paragraphs (a) through (d) of this section may represent the respondent upon an adequate showing, as determined by the hearing officer, that the individual possesses the legal, technical, or other qualifications necessary to advise and assist in the presentation of the case.