Categorization is the process of systematically identifying and classifying files according to content and relevance. In preparation for a PCI DSS audit, it is critical to identify which files fall within scope---those that contain cardholder data or impact its security.

Normalization adjusts data format, tokenization substitutes sensitive data with tokens, and anonymization removes identifiers. While useful, none directly address the task of isolating ''relevant files'' for audit. Categorization ensures that files are grouped correctly, allowing auditors to focus on the proper scope and preventing unnecessary exposure of unrelated data.

This step aligns with PCI DSS requirements that limit scope to systems and data directly affecting cardholder data security. Proper categorization streamlines audits and demonstrates effective data governance.