File Supplemental C Affidavit of Certification Form. Supplemental C Affidavit of Certification for the City of Oakland.Apply for a New Business Tax Certificate online or at the Business Tax Office. Refundable business registration fee plus special fees. Download PDF form to your computer first. The liber and page of the original recording is included in the recording fee. Free fillable forms: City of Oakland. Non-Federal Agency (CA) Sign up. TO PROCESS SERVER: You must serve the affidavit and claim no later than 7 days before the hearing date and file proof of service with the court clerk. If you are unable to complete service, you must return this original and all copies to the court clerk.