Which situation would be the most concerning for an organization that outsources IS processing to a private network during an audit?

The most concerning situation for an organization outsourcing IS processing to a private network during an audit is the absence of a right-to-audit clause in the contract with the third party. This clause is crucial as it grants the organization the authority to review the third party's compliance with the terms of the contract, particularly regarding security and processing of sensitive data. Without this right, the organization loses critical oversight over the third party’s operations, potentially leading to lapses in security, data breaches, or non-compliance with regulatory requirements. Organizations must ensure that they can verify the performance and security posture of outsourced services to maintain control and protect their data.

While the other situations mentioned may have significant implications, lacking a right-to-audit clause directly impacts the organization's ability to conduct oversight and assurance, making it the most serious concern.