Which of the following is a critical responsibility of notaries in their service?

Guaranteeing the identity of signers is a critical responsibility of notaries. This is fundamental to the notarial process, as it ensures that the person signing a document is who they claim to be. Notaries typically employ various methods to verify identity, such as checking government-issued identification and confirming that the signers are present and aware of the actions they are taking. This verification process helps to prevent fraud and enhances the integrity of the notarization process.

The other options do not align with the core responsibilities of a notary. Advising clients on the legal implications of documents exceeds a notary's role, as they are not authorized to provide legal advice. Collecting signatures without verification would undermine the purpose of the notary's function and could lead to invalid or fraudulent notarizations. Lastly, providing legal documentation to clients also falls outside the scope of a notary's responsibilities, as they facilitate the notarization of documents but do not create or issue legal documents themselves.