Who is considered a signer's witness in a co-located scenario?

In a co-located scenario, the witness is considered someone who is physically present in the same location as the signer. This proximity allows the witness to directly observe the signing event, ensuring that they can confirm the identity of the signer and attest to the authenticity of the signature. Being co-located also implies that the witness can provide immediate verification and support should any questions arise about the signing process, enhancing the integrity of the transaction.

The other options describe scenarios where the witness is not in the same physical space as the signer, which does not fulfill the criteria for a co-located witness. For example, witnesses who are in separate locations or appearing on different video feeds cannot directly observe the signing in real time, which weakens the credibility of the witnessing process. Furthermore, the role of a witness who signs on behalf of the signer is fundamentally different, as that person would not be witnessing the signing but rather acting on behalf of the signer. Thus, the focus on physical presence makes the identification of a co-located witness essential in this context.