The CMMC Assessment Process (CAP) requires that when sensitive or proprietary materials are exchanged during an assessment, the OSC and the C3PAO should establish confidentiality protections through a Non-Disclosure Agreement (NDA).

Extract:

“OSC and C3PAOs are expected to execute a Non-Disclosure Agreement (NDA) to protect sensitive information such as proprietary, attorney-client privileged, or pre-patent materials shared during the assessment process.”

Thus, the NDA is the correct document.