Explanation:

✅ C. All of the above, combined for a comprehensive assessment of report availability, accuracy, and functionality within the new system
Validating reports post-migration or during deployment requires both technical validation and requirement alignment. Reviewing report builder configurations and data source connections ensures the data fields, filters, and visual groupings reflect business requirements. Additionally, analyzing system logs and execution history helps detect backend issues such as data load failures, permission gaps, or runtime errors. When combined, these steps provide a full picture — ensuring the reports are not only present and functioning, but also accurate, compliant, and user-ready.

❌ A. Reviewing report builder configurations and data source connections to ensure alignment with defined reporting requirements
This step is crucial for validating logic, like filters, grouping, and field mappings. It ensures the report structure aligns with user expectations. However, it doesn’t confirm whether the report runs successfully, has backend errors, or contains accurate data — making it only part of the validation process.

❌ B. Analyzing system logs and report execution history to identify any errors or missing data within generated reports
While essential for identifying technical issues like failed queries or permission errors, this approach alone won’t verify whether the report design meets business needs or if the visual output is aligned with expectations. It helps assess reliability, not full business accuracy.

Reference:
🔗 Salesforce Help: Reports and Dashboards
🔗 Salesforce Help: Troubleshoot Reports
🔗 Salesforce Help: Get Verification Data