Rule 3133. Service of answers or objections to interrogatories. (a) Service of an answer or objection. Within twenty days after service of interrogatories, the party upon whom they are served shall serve upon each of the parties a copy of the answer to each interrogatory, except one to which the party objects, in which event the reasons for the objection shall be stated with reasonable particularity.

(b) Form of answers and objections to interrogatories. Interrogatories shall be answered in writing under oath by the party served, if an individual, or, if the party served is a corporation, a partnership or a sole proprietorship, by an officer, director, member, agent or employee having the information. Each question shall be answered separately and fully, and each answer shall be preceded by the question to which it responds.

(c) Amended answers. Except with respect to amendment or supplementation of responses pursuant to subdivision (h) of section 3101, answers to interrogatories may be amended or supplemented only by order of the court upon motion.