During an external audit of an organization's financial statements.

Responsibilities of an External Auditor:

When significant internal control deficiencies are discovered, the auditor is required to report them to senior management and, where appropriate, the audit committee.

The purpose is to ensure that the organization is informed of the risks and can take corrective actions.

Analysis of Other Options:

A. Suspend the audit:Not required under auditing standards.

B. Report to law enforcement:Only if fraud or illegal activities are confirmed, which is not implied here.

D. Correct deficiencies independently:This is beyond the auditor's scope of responsibilities.

Conclusion:The correct response is to provide a written communication about the findings to senior management.