C. Future State Description: A future state description articulates the desired outcome or vision for the improved process after implementing changes or enhancements. While it provides a unified vision for the future state of the process, it may not directly address the current issue of inconsistency in process models created from different user viewpoints. The future state description is more forward-looking and may not necessarily reconcile discrepancies or confusion in existing process models.

A: In contrast, the roles and permissions matrix specifically addresses the need to ensure coverage of activities, identify roles, associate them with solution activities, and designate authorities for performing these activities. By aligning roles and responsibilities across different user viewpoints, the roles and permissions matrix ensures consistency and clarity in how activities are depicted in the process models, thus addressing the stakeholders' concerns about inconsistency in the flows. Therefore, the roles and permissions matrix is the most suitable option in this context.