Defining clear, comprehensive, and testable requirements is critical before selecting and implementing a software product. Without well-documented requirements, the risk of choosing a solution that does not align with business needs increases significantly. A support contract (C) is important for long-term use, and escrow (D) may protect against vendor insolvency, but neither ensures that the product fits the organization's objectives. A post-implementation review (B) only evaluates success after implementation, which may be too late to correct fundamental misalignment. ISACA's COBIT framework (BAI03 and BAI05) stresses the importance of requirements gathering as the foundation for effective solution acquisition and development.
References (ISACA): COBIT 2019, BAI03 Managed Solutions Identification and Build; BAI05 Managed Organizational Change.