(2) At any time before the return day specified in the investigative demand, or within 20 days after the demand has been served whichever time is shorter, a petition to extend the return date, or to modify or set aside the demand, stating good cause, may be filed in the appropriate court.
(3) The investigative demand shall state the nature of the conduct constituting the alleged antitrust violation under investigation and the provisions of law believed to be applicable thereto. [1975 c.255 §13; 1977 c.729 §1]