Comprehensive and Detailed Step-by-Step Explanation: Conducting vulnerability assessmentsonly once per year, right before an audit,creates a false sense of securityandleaves systems exposedbetween assessments. * Annual Testing Before Audit (Correct Answer - A) * Risksundetected vulnerabilitiesfor extended periods. * Example:A company only tests security before acompliance audit, allowingzero-day threatsto persist for months. * Internal Team Conducting Assessments (Incorrect - B) * Not ideal, butregular assessmentsare more critical. * Focusing on Critical Systems (Incorrect - C) * Not perfect, butbetter than no testing at all. * Using Open-Source Tools (Incorrect - D) * Open-source toolscan be effective ifproperly configured. References: * ISACA CISA Review Manual * NIST 800-115 (Technical Guide to Security Testing)