Which of the following services can be classified as an assurance service? OA. The auditor verifies management's assertion about its disclosure of electronic commercial practices and evaluates the security of electronic data posted on the company's website. B. The auditor assesses the company's products for compliance with quality control standards required by the ISO 9000 certification. C. Any service that requires a CPA firm to issue a report about the reliability of an assertion that is made by another party. D. All of the above.