What proof of registration does the PSA use to mark the documentation?

The correct answer is based on the specific terminology used by the PSA (Public Service Agency) to denote the proof of registration within their procedural framework. The "Sign Up Stamp" serves as an official endorsement that signifies the successful registration of an individual or entity within the required system. This stamp is a tangible form of verification that indicates compliance with registration protocols, thus assuring that all necessary documentation has been processed and acknowledged.

The other options do not align with the established terminology or processes utilized by the PSA, which makes the "Sign Up Stamp" the most appropriate choice in this context. It effectively conveys the concept of an acknowledgment that something has been officially recorded and validated, which is essential in ensuring that all stakeholders are aware of and can verify the status of the registration.