'Supporting confidentiality' is the correct answer because the scenario describes a need to protect sensitive strategic communications from exposure, especially on less-secure networks where corporate espionage is a concern. Therefore, the primary goal is to maintain the privacy of data as it traverses potentially insecure networks. While 'Supporting non-repudiation' is important for accountability, 'Supporting integrity' is crucial for ensuring that data remains unchanged, and 'Supporting authentication' verifies entity identities, the scenario specifically emphasizes the need for privacy, not just authentication or integrity, making confidentiality paramount in this case. Despite 'Encrypted video conferencing' offering a form of confidentiality, it is a specific solution and may not cover all types of executive communications; hence, it is not as accurate as the general use case of 'Supporting confidentiality.'