Any person, who is required to appear before any authority appointed under section 10 or before the Tribunal or before an officer of the Bureau of Investigation constituted under section 86 in connection with any proceeding under this Act, may appear before such authority through--
         (a) a person authorised in the prescribed manner by him in this behalf, being his relative or person in his regular and whole time employment,
         (b) a sales tax practitioner who possesses the prescribed qualifications; or
         (c) a legal practitioner, or
         (d) subject to such conditions as may be prescribed, a chartered accountant, or company secretary, or cost accountant.
     Explanation.--For the purposes of this section,--
         (a) "chartered accountant" means a chartered accountant as defined in clause (b) of sub-section (1) of section 2 of the Chartered Accountants Act, 1949 (38 of 1949) and who has obtained a certificate of practice under sub-section (1) of section 6 of that Act;
        (b) "company secretary" means a company secretary as defined in clause (c) of sub-section (1) of section 2 of the Company Secretaries Act, 1980 (56 of 1980) and who has obtained a certificate of practice under sub-section (1) of section 6 of that Act;
         (c) "cost accountant" means a cost accountant as defined in clause (b) of sub-section (1) of section 2 of the Cost and Works Accountants Act, 1959 (23 of 1959) and who has obtained a certificate of practice under sub-section (1) of section 6 of that Act;
         (d) "legal practitioner" means an advocate, vakil or an attorney of any High Court, and includes a pleader in practice.