What type of information can the department require under an administrative subpoena?

The department can require the production of information or documents under an administrative subpoena because this legal tool is designed to obtain records that are relevant to a specific inquiry or investigation. Administrative subpoenas are typically used to ensure compliance with regulations and to gather necessary evidence without the need for a court order. This can include a wide variety of documents, such as business records, correspondence, or any other relevant materials that could provide insight into the matters at hand.

In contrast, the other options do not align with the scope of an administrative subpoena. For instance, verbal statements and personal testimonials do not usually provide the same concrete evidence as documented information. Meanwhile, while confidential business plans may be subject to subpoena under certain circumstances, they are not typically the standard type of information requested in the context of an administrative subpoena, as this process usually focuses more on identifiable records rather than proprietary or sensitive internal documents unless specifically justified.