The best recommendation to mitigate the risk of eavesdropping associated with an API integration implementation is to implement Transport Layer Security (TLS). TLS is a cryptographic protocol that provides secure communication over a network by encrypting the data in transit and authenticating the parties involved. TLS can prevent unauthorized parties from intercepting, modifying or tampering with the data exchanged between the API endpoints. Encrypting the XML file, implementing SOAP, and masking the API endpoints are not sufficient to mitigate the risk of eavesdropping, as they do not provide end-to-end encryption or authentication for the API communication. References: IS Auditand Assurance Tools and Techniques, CISA Certification | Certified Information Systems Auditor | ISACA