To prevent the situation where discrepancies identified by the auditor are corrected after being noted, it is essential to preserve the audit evidence. Taking screenshots or extracting tender documents would provide a permanent record of the discrepancies, ensuring that any subsequent changes do not invalidate the auditor's findings. This practice is crucial for maintaining the integrity of the audit evidence and supporting the audit conclusions. Option B is related but not as direct as preserving primary evidence. Options C and D do not address the preservation of evidence effectively.
Reference: The IIA's International Standards for the Professional Practice of Internal Auditing, Standard 2310 - Identifying Information.