8. To be authorized to carry on professional activities in accordance with this Regulation, a dispensing optician carrying on professional activities within a partnership or joint-stock company must furnish and maintain security, on behalf of the partnership or company, by means of an insurance or suretyship contract or by joining a group plan contract, against the professional liability of the partnership or company arising from fault on the part of the dispensing optician in carrying on professional activities within the partnership or joint-stock company.