Which of the following should be of GREATEST concern to an IS auditor reviewing project documentation for a client relationship management (CRM) system migration project?

Numerous defects in printing functionality five weeks prior to the target date are concerning but represent specific bugs that can be tracked and resolved within the project timeline, not a fundamental flaw in the migration strategy itself.

A holiday weekend migration may impact user availability for testing, but proper pre-migration testing and communication can mitigate this, and it does not inherently preclude a rollback strategy or phased approach.

Employee concerns about data representation indicate a need for user training and change management, which are important project aspects but not as critical as the architectural risk of a full cutover without a contingency plan.

A single-phase 'big bang' implementation with immediate cutover, especially for a critical system like CRM, is high-risk because it lacks a phased rollout or parallel run for validation and leaves no immediate fallback option if severe issues arise post-implementation. This approach can lead to significant business disruption if not meticulously planned and tested, and auditor concern arises from the lack of a graceful recovery strategy.