Within 30 days after service of the complaint or after the last publication of the notice, the contestee must file in the office where the contest is pending an answer specifically meeting and responding to the allegations of the complaint, together with proof of service of a copy of the answer upon a contestant as provided in § 4.450-5(b)(3). The answer shall contain or be accompanied by the address to which all notices or other documents shall be sent for service upon contestee.