Comprehensive and Detailed Step-by-Step Explanation:
Minimizing business downtime is critical when implementing a new system that supports an essential process like month-end closing.
* Option A (Incorrect):Thebig bang approachinvolves replacing the old system with the new system all at once. This method carries ahigh riskbecause if issues arise, they may causesignificant downtimeand disruption.
* Option B (Correct):Aphased approachgradually implements the system in stages, allowing users toadaptand minimizing the risk of complete failure. This strategy is ideal for critical systems that cannot afford extended downtime.
* Option C (Incorrect):Thecutover approachis a variation of big bang, where the old system is shut down, and the new system is activated. This method isriskyfor month-end processes because errors can causebusiness delays.
* Option D (Incorrect):Theparallel approachruns both old and new systems simultaneously to verify accuracy, but it isresource-intensiveand may not be practical for a high-volume month-end process.
Reference:ISACA CISA Review Manual -Domain 3: Information Systems Acquisition, Development, and Implementation- Covers system implementation strategies, risk management, and best practices.