Final answer:
Auditors must report any significant deficiencies in internal control to the audit committee, which is a central part of an organization's corporate governance responsible for overseeing financial reporting.
Step-by-step explanation:
The auditors who become aware of an internal control significant deficiency are required to communicate this to the audit committee. The audit committee is responsible for overseeing the financial reporting and disclosure process, and they serve as a key component in the corporate governance structure.
Communicating significant deficiencies to the audit committee is crucial as it ensures that those charged with governance are aware of any potential issues that could impact the reliability of financial reporting.
Therefore, the answer is C. audit committee.