Ind. Code § 8-1-13-35

Sec. 35. Any corporation receiving from the commission any blank forms with directions to complete them shall answer fully and correctly each question in the form, and if it is unable to answer any question, it shall give a good and sufficient reason for failing to answer the questions. The answers shall be verified under oath by the president, secretary, superintendent, or general manager, or person in charge of the corporation and returned to the commission at its office within the period fixed by the commission. Whenever required by the commission, every corporation shall deliver to the commission for examination any relevant documents, books, accounts, papers, and records (or copies), with a complete inventory of all its property in a form prescribed by the commission.