Which of the following is NOT part of PCI DSS requirements?

The choice stating "Conduct staff training on financial planning" is not part of the PCI DSS requirements because PCI DSS focuses specifically on the security measures necessary to protect cardholder data and ensure secure payment processes. The standards mandate specific practices and technical controls aimed at securing payment card information, including maintaining a secure network, proper usage of encryption, vulnerability management, and regular monitoring.

In contrast, the other options are integral parts of PCI DSS compliance. Maintaining a firewall configuration is crucial for protecting cardholder data networks from unauthorized access, while avoiding vendor-supplied defaults helps mitigate vulnerabilities due to standard system settings. Additionally, protecting cardholder data during transmission ensures that sensitive information is encrypted and secured while being sent across networks, thereby maintaining its confidentiality and integrity. These requirements are designed to reduce risks associated with data breaches and enhance overall security in payment card transactions.