CA Civ Proc Code Section 2033.210

(a)

The party to whom requests for admission have been directed shall respond in writing under oath separately to each request.

(b)

Each response shall answer the substance of the requested admission, or set forth an objection to the particular request.

(c)

In the first paragraph of the response immediately below the title of the case, there shall appear the identity of the responding party, the set number, and the identity of the requesting party.

(d)

Each answer or objection in the response shall bear the same identifying number or letter and be in the same sequence as the corresponding request, but the text of the particular request need not be repeated.