Using anonymized data in a non-production environment is the best approach for an organization in a heavily regulated industry to comprehensively test application functionality. Anonymized data is data that has been stripped of any personally identifiable information (PII) or other sensitive data, such as names, addresses, phone numbers, email addresses, etc. Anonymized data protects the privacy and security of the data, while still preserving the structure and format of the original data. Using anonymized data in a non-production environment allows the organization to test the application functionality without risking data breaches or violating regulations. Using production data, masked data, or test data in either production or non-production environments are not as optimal as using anonymized data, because they may introduce errors, inconsistencies, or vulnerabilities in the data or the application. References = Risk and Information Systems Control Study Manual, Chapter 3, Section 3.3.1, page 3-21.