Va. Code § 8.01-216.15
Each inquiry in a civil investigative demand served under this article shall be answered separately and fully in writing under oath and shall be submitted under a sworn certificate, in such form as the demand designates, by (i) in the case of a natural person, the person to whom the demand is directed, or (ii) in the case of a person other than a natural person, the person or persons responsible for answering each inquiry. If any inquiry is objected to, the reasons for the objection shall be stated in the certificate instead of an answer. The certificate shall state that all information required by the demand and in the possession, custody, control, or knowledge of the person to whom the demand is directed has been submitted. To the extent that any information is not furnished, the information shall be identified and reasons set forth with particularity regarding the reasons why the information was not furnished.
Va. Code § 8.01-216.15