Del. Fam. Ct. R. Civ. P. 33
(a) Availability; procedures for use. When discovery is permitted by the Court, any party may serve upon any other party written interrogatories to be answered by the party served or, if the party served is a public or private corporation or a partnership or association or governmental agency, by any officer or agent, who shall furnish such information as is available to the party.
(b) Answers and objections.
(1) Each interrogatory shall be restated as numbered and shall be answered separately and fully in writing under oath, unless it is objected to, in which even [event] the objecting party shall state the reasons for objection and shall answer to the extent the interrogatory is not objectionable.
(2) The answers are to be signed by the person making them, and the objections signed by the attorney making them.
(3) The party upon whom the interrogatories have been served shall serve a copy of the answers, and objections if any, within 30 days after the service of the interrogatories, except that a respondent may serve answers or objections within 45 days after service of the summons and complaint upon that respondent. The Court may allow a shorter or longer time. The party submitting the interrogatories may move for an order under Rule 37(a) with respect to any objection to or other failure to answer an interrogatory.
(4) All grounds for an objection to an interrogatory shall be stated with specificity. Any ground not stated in a timely objection is waived unless the party's failure to object is excused by the Court for good cause shown.
(5) The party submitting the interrogatories may move for an order under Rule 37(a) with respect to any objection to or other failure to answer an interrogatory.
(c) Scope; use at trial. Interrogatories may relate to any matters which can be inquired into under Rule 26(g), and the answers may be used to the extent permitted by the rules of evidence.
An interrogatory otherwise proper is not necessarily objectionable merely because an answer to the interrogatory involves an opinion or contention that relates to the fact or the application of law to fact, but the Court may order that such an interrogatory need not be answered until after designated discovery has been completed or until a pretrial conference or other later time.
(d) Option to produce business records. Where the answer to an interrogatory may be derived or ascertained from the business records of the party upon whom the interrogatory has been served or from an examination, audit or inspection of such business records, or from a compilation, abstract or summary thereof, and the burden of deriving or ascertaining the answer is substantially the same for the party serving the interrogatory as for the party served, it is a sufficient answer to such interrogatory to specify the records from which the answer may be derived or ascertained and to afford to the party serving the interrogatory reasonable opportunity to examine, audit or inspect such records and to make copies, compilations, abstracts or summaries. A specification shall be in sufficient detail to permit the interrogating party to locate and to identify, as readily as can the party served, the records from which the answer may be ascertained.
Del. Fam. Ct. R. Civ. P. 33