A data-quality review samples only the most recent successful files from one source. The pipeline also processes older files and several other sources with different formats. Which change improves the assessment?

1. Increase the number of rows from the same convenient source only and assume all sources are covered.
2. Use the file naming convention as proof that every row satisfies the quality rules.
3. Use a sampling plan that represents the relevant sources, time ranges, formats, and known failure conditions.
4. Exclude all quarantined records from every investigation because they are not published.