Comprehensive and Detailed Explanation:
A tabletop exercise is the most cost-effective method to test the BCP because it simulates scenarios and walks through responses without disrupting operations.
Stress test (A): More resource-intensive and may disrupt services.
Full operational test (C): Provides the highest assurance but is costly and disruptive.
Post-implementation review (D): Evaluates after actual incidents, not proactive.
# ISACA Reference: CISA Review Manual 27th Edition, Domain 2 (IT Operations and Business Resilience), section on BCP testing approaches.