(a) A copy of the petition is served on all other parties and the appropriate Regional Director by the petitioner.

(b) Interested persons may request intervention by a written motion to the Board. Such intervention may be granted at the discretion of the Board.

(c) Parties other than the petitioner may reply to the petition in writing, admitting or denying any or all of the matters asserted therein.

(d) No briefs shall be filed except upon special permission of the Board.

(e) After review of the entire record, the Board issues an advisory opinion as to whether the facts presented would or would not cause it to assert jurisdiction over the case if the case had been originally filed before it. The Board will limit its advisory opinion to the jurisdictional issue confronting it, and will not presume to render an opinion on the merits of the case or on the question of whether the subject matter of the dispute is governed by the Labor Management Relations Act.