(1) An Advisory Committee or the Central Advisory Committee may, at any time and for such period as it thinks fit, co-opt any person or persons to the Advisory Committee.
     (2) A person co-opted under sub-section (1) shall exercise all the powers and functions of a member under this Act but shall not be entitled to vote.
     (3) An Advisory Committee or the Central Advisory Committee may, if it considers it necessary or expedient so to do, invite any person to attend its meeting and when such person attends any meeting, he shall not be entitled to vote thereat.