In a Payroll Audit, a Staff Auditor Suspects That Signatures

In a payroll audit, a staff auditor suspects that signatures on some of the documents being sampled for examination are not authentic. What action should the auditor take before proceeding with the examination?

A) Suggest to the payroll manager that the suspicious documents should be sent to the organization's security department for forensic review.
B) Keep the suspicious documents in the workpaper file until the end of the engagement, and then discuss the suspicions with the payroll manager.
C) Discuss the suspicious documents with payroll staff to seek their views on the authenticity of the signatures.
D) Review the suspicious documents with the chief audit executive and seek advice concerning further examination.