What is the oath that the credible witness must take?

The correct choice articulates the specific responsibility of the credible witness when verifying the identity of a signer in a notarial act. When a credible witness is called upon, they must confirm that the signer is indeed the individual mentioned in the document being notarized. This affirmation is crucial because it ensures the integrity of the notarization process by establishing the identity of the signer based on the witness's personal knowledge.

This oath not only reinforces the ethical standards of notarization but also serves to protect against fraud. By swearing to the identity of the signer, the credible witness takes on a significant role in the verification process, making their statement vital for the authenticity of the legal document in question.

Other options lack the specificity necessary for the duties of a credible witness in this context. For instance, options asking for general promises to tell the truth or affirming one's own status as a notary do not adequately capture the unique responsibility of attesting to the identity of another individual involved in the signing process.