; (ii) cybersecurity experts; (iii) public interest advocates; and (iv) Federal employees with expertise in certification, covered devices, or cybersecurity, including employees of the Department of Commerce, the Federal Trade Commission, and the Federal Communications Commission. (C) Limitation In appointing members under subparagraph (A), the Secretary shall ensure that— (i) each interest group described in clauses (i) through (iv) of subparagraph (B) is proportionally represented on the Advisory Committee, including— (I) businesses of each size described in such clause (i); (II) Federal employees with expertise in each subject described in such clause (iv); and (III) Federal employees from each agency described in such clause (iv); and (ii) no single interest group is represented by a majority of the members of the Advisory Committee. (2) Chair The Secretary shall designate a member of the Advisory Committee to serve as Chair. (3) Pay Members of the Advisory Committee shall serve without pay, except that the Secretary may allow a member, while attending meetings of the Advisory Committee or a subcommittee of the Advisory Committee, expenses authorized under section 5703 of title 5, United States Code, relating to per diem, travel, and transportation. (d) Support staff