Which of the following BEST ensures that effective change management is in place in an IS environment?

Adequate testing by the development team is a part of the change process but doesn't ensure overall effective change management, as unauthorized changes could still bypass this.

User-prepared detailed test criteria for acceptance testing is important for quality but relates more to the testing phase of a change rather than the overarching control of the change process itself.

User authorization procedures for application access are a component of access control, not directly related to ensuring that system changes are managed effectively.

Well-controlled access to production source and object programs is critical because it directly prevents unauthorized or undocumented changes from being introduced into the live environment. This control ensures that all modifications follow the formal change management process, including review, testing, and approval, thereby maintaining system integrity and stability.