A vacancy in the membership of the National Committee occurs —
(a) on the death of a member;
(b) if a member resigns under section 7;
(c) if the appointment of a member is revoked under section 6;
(d) on the absence of a member from three consecutive meetings of the National Committee without presenting a medical certificate or without being excused, in writing, by the Chairperson; or
(e) at the expiration of the period of appointment of a member.