(a) To gather and compile information concerning, and to investigate from time to time the organization, business, conduct, practices, and management of any person, firm, or corporation engaged in intrastate commerce, and the relation thereof to other persons, firms, and corporations;
(b) To require, by general or special orders, persons, firms, and corporations engaged in intrastate commerce, or any class of them, or any of them to file with the commissioner, in such form as the commissioner may prescribe, annual or special, or both annual and special, reports or answers in writing to specific questions, furnishing to the commissioner such information as he may require as to the organization, business, conduct, practices, management, and relation to other persons, firms, and corporations, of the person, firm, or corporation filing such reports or answers in writing. Such reports and answers shall be made under oath, or otherwise, as the commissioner may prescribe, and shall be filed with the commissioner within such reasonable period as the commissioner may prescribe, unless additional time be granted in any case by the commissioner.