The most concerning finding for an IS auditor when evaluating information security governance within an organization is B. An information security governance audit was not conducted within the past year. According to the ISACA Certified Information System Auditor (CISA) Study Guide, information security governance audits should be conducted annually to ensure that the organization's information security policies and procedures are effective and up to date. Additionally, information security governance audits should assess the organization's risk management processes, control environment, and compliance with relevant laws and regulations. If an information security governance audit has not been conducted in the past year, then the organization may be at higher risk of data breaches and other security incidents.